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Health & Management / Rabbits and their Relatives: Disease Investigation and Management / List of hyperlinked Techniques & Protocols:

Clinical Pathology of Lagomorphs:

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Introduction and General Information

Clinical pathology of lagomorphs follows the same general principles as for other species. However, there are some aspects in which normal findings, abnormal findings, and interpretation are different from those of other species such as cats and dogs. It is important to be aware of these differences.
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Haematology

Sample collection

Blood can be collected from a variety of sites: the jugular vein, cephalic vein, marginal ear vein, recurrent tarsal or lateral saphenous vein, also from the central auricular artery and the medial saphenous artery.

  • For further information on blood sampling and the advantages and problems associated with different sites see: Blood Sampling Rabbits
  • Blood volume is 57 - 78 mL/kg. (J213.2.w3); about 55 - 65 mL/kg. (J29.16.w6); 57 +/- 4.8 - 69.8 +/- 9.1 mL/kg (from different studies). (B611.3.w3)
  • Note: useful information can be obtained from very small blood samples:
    • Only a few drops of blood are needed for haematocrit, total protein, white cell differential (from a blood smear) and white cell count. (J213.9.w4)
  • Because of the differences in the cells between different species, it is important that whoever is carrying out a complete blood cell count is familiar with the species. (B601.4.w4)
  • Several air-dried smears should be made immediately following blood collection, before cell morphology is affected by anticoagulant or transport. (J29.16.w6)
    • "A well-prepared air-dried smear is required for an accurate differential white cell count and evaluation of the cytological appearance of each cell type." (J29.16.w6)
Haematological parameters

Published normal values for individual lagomorph species are provided in:

Haematocrit (packed cell volume, PCV)

  • Normal 33 - 50%. (B601.4.w4)
    • In pet rabbits, generally 30 - 40%, with < 30% indicating anaemia and > 45% suggesting dehydration, often associated with gastric stasis. (B600.6.w6, J29.16.w6, J60.13.w2)
    • In one study, 40.2 +/- 14% (0.401 +/- 0.14 L/L) in rabbits kept outside in a garden or large, fully enclosed outside area, with a slightly lower mean in rabbits kept in a hutch and with normal teeth, and those with early dental disease, and significantly lower in those with advanced dental disease. (J8.42.w3)
  • Higher in males than in females, and in older than in younger animals. (B601.4.w4)
  • Usually determined from PCV measured by centrifugation. (B601.4.w4)
    • Can be measured directly by automated flow cytometry. (B601.4.w4)
  • Note: in rabbits with lymphosarcoma, the haematocrit (10 - 25%), haemoglobin (35 - 75 g/L) and total rbc count (as low as 2 x 1012/L) are reduced and fluctuating (while the total wbc count is generally not reduced). (J420.45.w1)

Haemoglobin

  • 100 - 150 g/L (B601.4.w4)
    • May be as low as 35 - 75 g/L in rabbits with lymphosarcoma. (J420.45.w1)

Erythrocytes

  • Normal range 5.1 - 7.6 x 1012/L. (B601.4.w4); 
    • Average diameter 6.7 - 6.9 m (range 5.0 - 7.8 m) (B601.4.w4, B614.7.w7) and thickness 2.15 m. (B601.4.w4)
    • Average diameter 6.6 m, thickness 2.15 m. (B463.1.w1)
    • Average diameter 6.5 - 7.5 m, thickness 2.4 m. (B611.3.w3)
    • 5.0 - 7.8 m. (J29.16.w6, B614.7.w7)
    • Average diameter 6.7 - 6.9 m, average thickness 2.15 - 2.4 m. (B461.170.w170)
    • Biconcave discs.
    • Thickness 2.15 - 2.4 m. (B614.7.w7)
    • In newborns, erythrocytes are larger and may be > 9m diameter; adult values are reached by 20 - 120 days. (B611.3.w3)
  • MCV 60 - 69 fl (B601.4.w4); 68.3 fl. (J213.2.w3)
  • MCH 19 - 22 pg (B601.4.w4)
  • MCHC 30 - 35% (B601.4.w4)
  • Rabbit rbc lifespan:
    • Potential lifespan of 67 days, mean 57 days, random rate of destruction 0.5% per day. (B461.170.w170, B601.4.w4, B614.7.w7)
    • Mean about 50 days, as low as 45 days and as high as 68 days reported. (B611.3.w3)
    • 45 - 70 days. (B461.170.w170, J213.2.w3)
    • 57 days. (J29.16.w6)
  • Erythrocyte sedimentation rate:
    • 1 - 4 mm/hour (B611.3.w3); 2 - 4 mm/hr (B16.2.w2)
      • For females, range 1 - 3 mm/hr, mean 2.0 +/- 0.5 mm/hr; for males range 0.95 - 2.55 mm/hr, mean 1.75 +/- 0.4 mm/hr. (B461.170.w170)
  • Normal variations in rabbits
    • It is normal to find anisocytosis of up to 2% of rbc in healthy rabbits. (B600.6.w6, B601.4.w4, B603.2.w2, B611.3.w3) Some blood cells are only a quarter of normal size. (B461.170.w170)
    • Polychromasia may be seen as a normal finding in rabbits. (B600.6.w6, B603.2.w2, B611.3.w3); this is due to the short lifespan and therefore high turnover of rbc. (J29.16.w6, J60.13.w2) Polychromasia may be noted in 1 - 2% of cells. (B461.170.w170)
    • Occasional nucleated rbc (1 - 2 per 100 leucocytes) (J29.16.w6) can be seen in normal rabbits. (B600.6.w6, B601.4.w4, B603.2.w2, B614.7.w7)
    • Howell-Jolly bodies occur occasionally in normal rabbits. (B601.4.w4, B603.2.w2, B614.7.w7, J29.16.w6, J60.13.w2)
    • Reticulocytes usually account for 2 - 4% of rbc, (B601.4.w4, B611.3.w3, B614.7.w7); 1.4 - 3.9% (J213.2.w3); 1 - 4% (J29.16.w6); more in young animals. (B601.4.w4) 1 - 7%, average 2.0 +/- 0.5% in male rabbits, 3.0 +/- 0.5% in female rabbits. (B461.170.w170)
    • In juveniles there may be more reticulocytes, e.g. 7.4 +/- 4.7% in New Zealand white rabbits at one- to two-months-old. (B461.170.w170)
  • With regenerative anaemia:
    • Anisocytosis, polychromasia, nucleated RBCs, Howell-Jolly bodies present. (J213.2.w3)
    • Reticulocytes increase following blood loss; (B601.4.w4) including following repeated blood collections. (B461.170.w170)
  • With acute infection, there may be a reduced total RBC count and an increase in nucleated rbc. (J213.2.w3)
  • With chronic disease such as lead toxicity, abscessation, endocarditis and pasteurellosis, anaemia is generally present. (J213.2.w3)
  • With endothelial damage: increased nucleated rbc. (J213.2.w3)

Platelets (thrombocytes)

  • Cytoplasm pale blue to colourless, containing a small cluster of azurophilic granules (Romanowsky stains, e.g. Wright's stain) giving an intense violet colour centrally. (B601.4.w4, B611.3.w3)
  • Singly or in clumps; (B601.4.w4, B611.3.w3, B614.7.w7); usually in small clusters. (B461.170.w170)
  • Oblong or oval to round. (B611.3.w3)
  • Usually 1 - 3 m diameter, sometimes larger. (B601.4.w4, B611.3.w3, B614.7.w7)
  • Usually 250 - 650 x 109/L, normal range 170 - 1120 x 109/L (B601.4.w4) 3 - 5 x 105/Ll. (B614.7.w7)
  • Reported ranges vary 126 - 1000 x 103/mm, (B461.170.w170)
  • Thrombocytopaenia may be seen with acute infection, disseminated intravascular coagulation, haemorrhage, or falsely in samples which have clotted or which have developed micro-clots (possibly due to insufficient mixing of the sample following venipuncture). (B603.2.w2, V.w131)

Leucocytes

  • Normal range 5.2 - 12.5 x 109/L. (B601.4.w4) 7000 - 9000 /l. (B614.7.w7)
  • This varies with age, sex, breed and season. (B600.6.w6, B601.4.w4)
  • There is a diurnal variation: counts are lowest in late afternoon/evening. (B600.6.w6, J29.16.w6)
  • With acute infection, the wbc rarely increases, but the differential wbc count usually changes; the neutrophil percentage may be 60% or greater and lymphocytes 30% or lower. Occasionally the total wbc count is reduced and the differential count is unchanged. (B601.4.w4, J213.2.w3)
  • With stress or administration of endogenous corticosteroids, significant lymphopaenia can occur. (B601.4.w4, J213.2.w3)
  • With lymphoma, the wbc cell count is generally normal or reduced (aleukaemic) with relative lymphophilia (80 - 90% lymphocytes) and both immature and atypical lymphocytes present. (B601.4.w4, J213.2.w3, J420.45.w1)
  • This count varies; there are diurnal variations, nutritional effects, age, gender and breed differences, and fluctuations within an individual over time. (B461.170.w170)
  • Counts are lowest in newborns and juveniles, increasing with age to reach adult values after a year old. (B461.170.w170)

Lymphocytes

  • Normally the commonest white blood cell, (B611.3.w3, B614.7.w7, J213.2.w3) 30 - 80% of the total WBC count. (B601.4.w4) typically 60% (J213.2.w3)
  • Usually 7 - 10 m diameter (about the same size as rbc), occasionally larger cells (10 - 15 m) (about the same size as mature neutrophils). (B601.4.w4, B611.3.w3, B614.7.w7, J213.2.w3)
    • The larger cells sometimes contain azurophilic granules. (B614.7.w7, J213.2.w3)
  • Cytoplasm medium to dark blue with Romanowsky stains. (B601.4.w4, B614.7.w7)
  • Nucleus round to oval, dark purple-blue. (B601.4.w4); round, pyknotic. (B461.170.w170)
  • Nucleus sometimes surrounded by a non-B601halo. (B601.4.w4, B611.3.w3, B614.7.w7)
  • The cytoplasm sometimes contains azurophilic granules; (B601.4.w4, B611.3.w3) particularly in larger lymphocytes. (B461.170.w170)
  • In healthy rabbits, 39% (range 21 - 55%) are B-lymphocytes, 44% (range 40 - 69%) T-lymphocytes and 8% (range 4 - 15%) null cells. (B614.7.w7, J495.32.w3)
  • In two-month-old rabbits, 60% of leucocytes were lymphocytes, decreasing to 45% by one year. (B461.170.w170)
  • Lymphopaenia may be seen with a variety of diseases. Relative lymphopaenia (relative neutrophilia) may be seen associated with stress. (B600.6.w6)
  • With lymphoma, the wbc cell count is generally normal or reduced (aleukaemic) with relative lymphophilia (80 - 90% lymphocytes) and both immature and atypical lymphocytes present. (B601.4.w4, J213.2.w3, J420.45.w1)

Monocytes

  • Normally 0 - 4% of white blood cells. (B601.4.w4)
  • 15 - 18 m diameter. (B461.170.w170, B601.4.w4, B614.7.w7); the largest white blood cells. (B614.7.w7, J213.2.w3)
  • Cytoplasm abundant, staining grey to blue-grey with Romanowsky stains. (B601.4.w4, B614.7.w7, J213.2.w3)
    • A few vacuoles may be present. (B461.170.w170, B601.4.w4, B614.7.w7)
    • With non-specific toxicity, dark red granules may be seen. (B601.4.w4, B611.3.w3)
  • Nucleus large, variable in shape (amoeboid) (lobulated, horseshoe or bean-shaped) (B461.170.w170, B614.7.w7), chromatin may be less condensed than in neutrophils. (B601.4.w4, B611.3.w3, J213.2.w3) (lightly staining and diffuse). (B461.170.w170, B614.7.w7)
  • A few vacuoles may be present in the nucleus. (B611.3.w3)
  • There is no non-staining halo around the nucleus. (B611.3.w3, J213.2.w3)
  • Monocytosis may be noted with chronic infection or inflammation. (B600.6.w6, J29.16.w6, J60.13.w2)

Neutrophils

  • Normally 20 - 75% of white blood cells. (B601.4.w4); the second commonest wbc (after lymphocytes). (J213.2.w3)
  • In two-month-old rabbits, 40% of leucocytes were neutrophils, increasing to 45% by one year. (B461.170.w170)
  • Rabbit neutrophils contain eosinophilic granules. Therefore these cells are sometimes termed heterophils, amphophils, pseudoheterophil or pseudoeosinophil. (B461.170.w170, B463.2.w2, B601.4.w4, B611.3.w3, B614.7.w7, J213.2.w3, P113.2005.w2)
  • Compared with eosinophils, the granules are smaller and do not fill the cytoplasm. (B463.2.w2, P113.2005.w2)
  • Neutrophils are smaller than eosinophils:
    • 7 - 11 m, (B611.3.w3, J72.49.w1, P113.2005.w2) compared with eosinophils at 10 - 15 m. (B611.3.w3, J72.49.w1, P113.2005.w2)
    • 10 - 15 m (B601.4.w4, B614.7.w7) versus eosinophils at 12 - 16 m. (B601.4.w4)
  • Nucleus polymorphous, staining light blue and light purple. (B611.3.w3, B614.7.w7); light purple, with the nuclear membrane light blue. (B461.170.w170)
  • There are actually two different types of granules in the rabbit neutrophil, one is only found in the progranulocytes. (J213.2.w3)
  • There are abundant small pink-staining granules and fewer large darker pink to red staining granules. (B461.170.w170, B614.7.w7)

Eosinophils

  • Normally 0 - 4% of the wbc. (B601.4.w4)
  • Diameter 10 - 15 m (B611.3.w3); 12 - 16 m (B461.170.w170, B601.4.w4, B614.7.w7) - larger than the neutrophil. (B461.170.w170, B601.4.w4, J213.2.w3)
  • Granules are large (3 - 4 times the size of granules in rabbit neutrophils), stain dull pink-orange or intense pink with Romanowsky stains (i.e. intensely acidophilic), and generally fill the cytoplasm. (B461.170.w170, B601.4.w4, B611.3.w3, B614.7.w7, J213.2.w3)
  • Nucleus horse-shoe shaped or bilobed. (B461.170.w170, B601.4.w4, B614.7.w7, J213.2.w3); usually fewer lobes than in neutrophils. (B463.2.w2)
  • Usually in inverse proportion to tissue mast cells. (B614.7.w7)
  • Eosinophilia may be seen associated with chronic parasitism particularly when parasites are migrating through tissue, and with diseases of tissues such as the skin, lungs, GIT and uterus, which contain large numbers of mast cells. (B460.1.w1, B600.6.w6)
    • In rabbits, mild eosinophilia may occur with chronic parasitism (e.g. ascarid infections). (B600.6.w6)
    • Slight to moderate eosinophilia may occur following repair of traumatic injuries in rabbits. (B600.6.w6)

Basophils

  • Commonly seen in rabbit blood (B461.170.w170, B460.1.w1, B600.6.w6, B614.7.w7); normally 0 - 7% of wbc in rabbits. (B601.4.w4); 0 - 5% (B614.7.w7)
    • Can even be up to 30% of the differential WBC count in some normal rabbits. (B611.3.w3, B614.7.w7, J213.2.w3)
    • The number of circulating basophils is inversely proportional to the number of tissue mast cells. (B461.170.w170)
  • Size similar to neutrophils. (B601.4.w4, B611.3.w3, B614.7.w7, J213.2.w3); 7 - 11 m (J72.49.w1); 8 - 12 m. (J29.16.w6)
  • Cytoplasm dark purple to purple-black, sometimes metachromic.  (B601.4.w4, B611.3.w3, B614.7.w7, J29.16.w6, J213.2.w3)
  • Nucleus lobulated, light purple. (B461.170.w170, B601.4.w4, B611.3.w3, B614.7.w7, J213.2.w3)
    • This may be obscured by the cytoplasmic granules, which are metachromic and purple to black. (B611.3.w3, J29.16.w6, J213.2.w3)

Clotting parameters

  • Activated clotting time: 4.0 +/- 0.4 minutes; 4.3 +/- 0.6 minutes; 4.4 minutes (three studies; mean +/- SD). (B614.7.w7)
  • Activated partial thromboplastin time: 15.7 - 42.7 s in one study, 19.5 - 22.5 s in another study. (B614.7.w7)
  • Prothrombin time (PT): 7.5 +/- 0.3 s (mean +/- SD)
  • Thrombin time (TT): 9.9 +/- 2.1 s (mean +/- SD)
  • Bleeding time: 1.4 +/- 0.3; 1.9 +/- 0.8; 2.1 +/- 0.5; 4.6 +/- 0.5; 5.4 +/- 1.2 minutes (five studies; mean +/- SD). (B614.7.w7)
Normal variations and non-disease factors affecting parameters
  • Diurnal variation:
    • Total white blood cell count and lymphocyte counts are lowest in late afternoon and evening, while neutrophil and eosinophil counts rise at this time. (B611.3.w3, B614.7.w7, J29.16.w6, J60.13.w2)
    • Monocytes and basophils are at their lowest values in the early morning, and highest "about 12 hours later". (B611.3.w3)
  • Age:
    • Lower counts for both RBC and WBC in juveniles. (J60.13.w2)
    • RBC counts are lowest in newborns and juveniles, increasing with age to reach adult values after a year old. (B461.170.w170)
      • In neonates, haemoglobin level is similar to that seen in adults, but PCV is higher. By 20 days, both have declined by about 30%, and by 90 days they have risen to adult levels. (B614.7.w7)
      • In neonates, erythrocyte counts are low (about 4.4 x 109/L), then counts increase to 90 days. (B614.7.w7)
      • In neonates, PCV and MCHC are similar to those of adults, rbc count is reduced, MCV is high as is MCH. (B614.7.w7)
      • In neonates, WBC count is low, increasing to adult levels by 90 days. (B614.7.w7); there is a peak WBC count at 90 days, dominated by lymphocytes, and a second peak at over one year, with more neutrophils (while lymphocyte counts have reduced). (B614.7.w7)
  • Stress due to e.g. transportation, unfamiliar surroundings, or waiting in a room where cats, dogs etc. are present:
    • Relative neutrophilia and lymphopaenia. (B600.6.w6, B603.2.w2, J29.16.w6, J495.40.w4)
  • The Pelger-Huet nuclear abnormality, with neutrophils having unsegmented or minimally segmented nuclei, may be found in normal rabbits. (B461.170.w170)
  • Haemolysis of the blood sample will lead to an artefactually low PCV. (J60.13.w2)
Findings associated with disease
By findings
  • Reduced blood cellularity (anaemia and lymphopaenia) is a non-specific finding in diseased rabbits. (B600.6.w6)
  • Leucocytosis may not occur even with infection or inflammation. (B601.4.w4, J29.16.w6, J60.13.w2, J213.2.w3)
  • Elevated PCV and total proteins: dehydration. (B603.2.w2, J60.13.w2)
  • Regenerative anaemia
    • Anisocytosis, polychromasia, nucleated RBCs, Howell-Jolly bodies present; these can also be seen in normal rabbits. (B603.2.w2, J213.2.w3)
    • Regenerative anaemia may be associated with acute blood loss such as wounds, liver or spleen rupture due to trauma (seen after 2-3 days), or chronic blood loss, as seen with heavy flea burdens or chronic intermittent bleeding (e.g. uterine endometrial aneurism, uterine adenocarcinoma, urolithiasis, chronic bleeding from the gut). (B600.6.w6, B603.2.w2, J29.16.w6, J60.13.w2)
    • Lead Poisoning. Presence of nucleated red blood cells, poikilocytosis, hypochromasia and basophilic cytoplasmic stippling. (B600.6.w6, B603.2.w2, J29.16.w6)
    • Neutrophilia may occur with haemolytic or haemorrhagic anaemia. (B603.2.w2)
    • Bleeding disorders, including haemolyic anaemia associated with thymoma and lymphosarcoma. (B603.2.w2)
  • Non-regenerative anaemia
    • May be seen with lymphoma or chronic renal disease. (B600.6.w6, J60.13.w2)
    • Mild non-regenerative anaemia with chronic diseases. (B600.6.w6, J29.16.w6, J60.13.w2, J213.2.w3)
    • Acute blood loss (initial).
  • Monocytosis:
    • Chronic infection/inflammation. (B600.6.w6, J29.16.w6, J60.13.w2)
  • Eosinophilia:
    • Chronic parasitism. (J29.16.w6, J60.13.w2, J213.2.w3)
  • Leucopaenia:
    • Chronic stress. (J29.16.w6)
    • Sometimes seen with acute infection. (B601.4.w4, J29.16.w6, J213.2.w3)
  • Relative lymphophilia:
  • Relative neutrophilia and lymphopaenia:
By disease/condition
  • In general, diseased rabbits show anaemia, increased neutrophils and reduced lymphocytes. (B614.7.w7, J83.16.w3)
  • With acute infection, there may be a reduced total RBC count and an increase in nucleated RBC. (B600.6.w6, J29.16.w6, J213.2.w3)
  • With chronic disease such as lead toxicity, abscessation, dental disease, endocarditis and pasteurellosis, a degree of anaemia is generally present. (B600.6.w6, J213.2.w3, J60.13.w2); mild non-regenerative anaemia. (J29.16.w6, J60.13.w2)
  • With endothelial damage: increased nucleated rbc. (J213.2.w3)
  • With acute infection, the wbc rarely increases, but the differential wbc count usually changes; the neutrophil percentage may be 60% or greater and lymphocytes 30% or lower. Occasionally the total wbc count is reduced and the differential count is unchanged. (B601.4.w4, J4.195.w3, J29.16.w6, J213.2.w3)
  • With stress or administration of endogenous corticosteroids, significant lymphopaenia can occur. (B601.4.w4, J213.2.w3)
    • With prolonged stress, a relative neutrophilia may also be noted. (B600.6.w6)
    • With chronic stress (raised cortisol), leukopaenia and lymphopaenia may be present, also eosinopaenia. (J29.16.w6)
  • With lymphoma, the wbc cell count is generally normal or reduced (aleukaemic) with relative lymphophilia (80 - 90% lymphocytes) and both immature and atypical lymphocytes present. (B601.4.w4, J213.2.w3, J420.45.w1)
    • High wbc counts can occur with lymphosarcoma. (B600.6.w6, J29.16.w6)
  • With chronic disease often low wbc count. (B600.6.w6)
  • With chronic infection/inflammation, monocytosis may be noted (but does not always occur). (B600.6.w6, J29.16.w6, J60.13.w2)
  • With chronic parasitism low-grade eosinophilia. (J213.2.w3)
  • With Rabbit Haemorrhagic Disease, prolonged prothrombin time (PT) and activated partial thrombin time (APTT) (disseminated intravascular coagulation occurs). (J213.2.w3)
  • In Lead Poisoning in rabbits, regenerative anaemia with nucleated erythrocytes, hypochromasia, poikilocytosis and basophilic cytoplasmic stippling. (J29.16.w6)
  • With chronic skin disease such as atopy or pyoderma, basophilia plus eosinophilia may occur. (J29.16.w6)
  • With dehydration:
    • Increased PCV and total proteins. (B603.2.w2, J60.13.w2)
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Clinical Biochemistry

Sample collection
Blood can be collected from a variety of sites: the jugular vein, cephalic vein, marginal ear vein, recurrent tarsal or lateral saphenous vein, also from the central auricular artery and the medial saphenous artery.

For further information on blood sampling and the advantages and problems associated with different sites see: Blood Sampling Rabbits

  • Note: useful information can be obtained from very small blood samples.
    • Complete plasma chemistry can often be run using less than 1 mL of blood. (J213.9.w4)

Note: Ranges of normal values from different studies or laboratories may vary markedly. (B600.6.w6)

Biochemical parameters

Published normal values for individual lagomorph species are provided in:

Normal variations and non-disease factors affecting parameters
  • Prolonged stress: (e.g. transportation, waiting in unfamiliar surroundings:
    • Increased glucose. (B603.2.w2)
    • Hyperglycaemia, elevated cortisol. (J495.40.w4)
  • Physical restraint:
    • Increased LDH, AST and CK. (B603.2.w2)
  • Haemolysis of the sample:
    • Increased LDH, AST, CK, total protein and potassium. (B603.2.w2)
    • Decreased amylase. (B603.2.w2)
  • Use of oxyglobin: artefactural changes in several parameters. (B603.2.w2)
Findings associated with disease

Note: in rabbits, none of the enzymes which may be increased with hepatocellular damage are specific to the liver, although a combination of several of these enzymes being raised may suggest liver damage. (J60.13.w2)

Total Protein

  • Excessive venous stasis during sample collection (e.g. sampling from small blood vessels in small rabbit breeds or in kits) can cause an artefactural increase in total protein concentration - fluid and small molecules leave the plasma during the period of collection, producing a relative increase in proteins. (B600.6.w6)
  • There are breed and strain variations. (J213.2.w3)
  • Increased total proteins (hyperproteinaemia) are seen with:
    • Dehydration (e.g. water deprivation, gastro-intestinal disturbances). (B600.6.w6, J29.16.w6, J60.13.w2)
    • Chronic disease. (B600.6.w6, J29.16.w6, J60.13.w2)
    • Immune-mediated disease. (B600.6.w6, J60.13.w2)
    • Hypovolaemia. (J213.2.w3)
    • Prolonged hyperthermia. (J213.2.w3)
    • Haemolysis. (B603.2.w2)
  • Decreased total proteins (hypoproteinaemia) are seen with:
    • Liver disease; (B600.6.w6, J29.16.w6, J213.2.w3)
    • Renal disease such as glomerulonephropathy. (B600.6.w6, J213.2.w3)
    • Chronic enteropathy; (B600.6.w6)
    • Malnutrition or starvation. (B600.6.w6, J29.16.w6)
    • Increased loss of protein:
      • Rarely in rabbits, glomerulonephropathy or protein-losing enteropathy. (B600.6.w6, J29.16.w6, J60.13.w2)
      • Loss of proteins through burns, haemorrhage or flystrike wound exudation. (B600.6.w6, J29.16.w6, J60.13.w2)

Albumin

  • Albumin is synthesised in the liver. (B600.6.w6, B460.4.w4)
  • Lower albumin may be noted in does during pregnancy. (J213.2.w3)
  • Hypoalbuminaemia is seen in advanced liver disease (J213.2.w3), including parasitism. For example:
  • Note: "liver failure and hepatocellular damage are not synonymous and liver failure should not be rejected as a cause of hypoalbuminaemia just because liver enzymes are not elevated." (B460.4.w4)
  • Hypoalbuminaemia may also be seen associated with:
    • Nutritional problems associated with lack of caecotrophy, incorrect diet, or starvation/malnutrition due to dental disease; (B600.6.w6, J29.16.w6)
    • Renal disease; (J213.2.w3) glomerulonephropathy; (B600.6.w6) interstitial nephritis (J13.19.w1)
    • Protein-losing enteropathy; (B600.6.w6, J213.2.w3)
    • Malabsorption; (B600.6.w6)
    • Cardiogenic ascites; (B600.6.w6)
    • Extensive burns (Burns) or wound exudation (e.g. with fly strike (Myiasis)). (B600.6.w6, B460.4.w4)
    • Haemorrhage (alongside anaemia and lowered globulins). (B600.6.w6, B460.4.w4)
  • Hyperalbuminaemia together with raised PVC indicates dehydration. (B600.6.w6)
  • Hyperalbuminaemia (alongside raised globulins) may be seen with haemolysis. (B603.2.w2)

Globulins

  • Plasma globulins include a wide range of proteins including immunoglobulins (gamma-globulins). (B600.6.w6)
  • Raised globulins, particularly gamma globulins may be seen with: (B600.6.w6)
  • Reduced globulins may be seen with:
    • Haemorrhage (alongside anaemia and hypoalbuminaemia). (B600.6.w6)
    • Extensive burns (Burns) or wound exudation (e.g. with fly strike (Myiasis)). (B600.6.w6)

Fibrinogen

  • In young rabbits normally < 200 mg/dL and in adults 200 - 400 mg/dL. (J213.2.w3)
  • Increased in cold-stressed rabbits. (J213.2.w3)
  • Not necessarily raised in rabbits with acute inflammation. (J213.2.w3)

Glucose

  • Serum glucose does not fall in fasting rabbits (after e.g. 48 - 96 hours of food being withheld) (B600.6.w6, B611.3.w3, J29.16.w6) except in neonates (under 15 days old). (B601.4.w4)
  • There may be differences in normal serum glucose concentrations between different breeds of rabbit. (B611.3.w3)
  • Hypoglycaemia can be seen with:
  • Hyperglycaemia may be seen with:
    • Stress, including heat stress, fear, pain, stress of transportation, and handling, and with haemorrhage and traumatic shock. (B600.6.w6, B601.4.w4, J29.16.w6, J60.13.w2, J213.2.w3)
    • In association with gut stasis; this may suggest Hepatic Lipidosis in Rabbits and appears to indicate a poor prognosis. (B600.6.w6, J29.16.w6)
    • With acute intestinal blockage (e.g. glucose 20 - 25 mmol/L, returning to normal after the condition is treated successfully). (B600.6.w6)
    • Heat stress (Hyperthermia - Sunstroke - Heatstroke in Waterfowl, Elephants, Bears, and Lagomorphs) - glucose may be dramatically increased. (J400.97.w1)
    • Early in mucoid enteritis. (J29.16.w6, J213.2.w3)
    • Some anaesthetics, such as halothane. (J213.2.w3)
    • Glucocorticoids. (J29.16.w6)
    • Diabetes mellitus. (J45.109.w1)
      • Note: Raised serum glucose is unlikely to indicate diabetes mellitus in rabbits; this is extremely rare in pet rabbits although it has been seen in New Zealand white laboratory rabbits. (B601.4.w4)
  • Serum fructosamine has been measured at 247.66 - 335 umol/L in 47 healthy pet rabbits; this might rise in diabetic rabbits. (B601.4.w4)

Blood urea nitrogen (BUN)

  • Urea is the end-product of protein catabolism and is produced in the liver. (B600.6.w6, B601.4.w4)
  • Urea is filtered by the glomerulus, with 25-40% being reabsorbed in the renal tubules. (B601.4.w4)
  • Diurnal variation in rabbits, with a peak in late afternoon/early evening. (B600.6.w6, B601.4.w4, J29.16.w6, J213.2.w3)
  • There is some variation with breed and sex. (J213.2.w3)
  • Increased BUN may be:
    • Associated with high protein diet, vigorous exercise or other causes of increased protein catabolism. (B614.7.w7)
      • Gastrointestinal haemorrhage leads to increased protein digestion and therefore azotaemia. (J29.16.w6)
    • Prerenal - reduced renal blood flow or reduced filtration pressure at the glomerulus (e.g. with dehydration/water deprivation). (B600.6.w6, B601.4.w4, J29.16.w6, J60.13.w2)
      • Note: with raised BUN due to water deprivation/dehydration, level should return to normal following rehydration. (B600.6.w6, J29.16.w6, J60.13.w2)
      • Reduced renal blood flow due to shock or cardiac disease. (J29.16.w6)
    • Renal: loss of at least 50-70% of nephrons. (B601.4.w4, J213.2.w3, J60.13.w2)
    • Post-renal: obstruction due to urolithiasis or neoplasia, also with perforation of the urinary system. (B601.4.w4, J213.2.w3)
  • Decreased BUN may be associated with: (B601.4.w4, B614.7.w7)
    • Anabolic steroids
    • Insufficient protein intake
    • Severe hepatic insufficiency. 

    (B600.6.w6, B601.4.w4, B614.7.w7, J213.2.w3)

Creatinine

  • Mainly an endogenous product of creatine metabolism by muscle. (B614.7.w7, J213.2.w3)
  • Creatinine is filtered freely into the glomerular filtrate at the same concentration as it is present in plasma. (B614.7.w7, J213.2.w3)
  • Increased with severe renal insufficiency (loss of at least 50 - 70% of nephrons). (B601.4.w4, B614.7.w7, J213.2.w3)
  • Increased with decreased renal blood flow. (J213.2.w3)
    • Note: with raised serum creatinine due to water deprivation/dehydration, level should return to normal following rehydration. (B600.6.w6, J60.13.w2)
  • Increased with severe muscle damage. (B601.4.w4, B614.7.w7)
  • May be increased with Aflatoxicosis. (J495.43.w6)
  • Note: not reliable in samples taken more than 24 hours before testing is carried out. (B600.6.w6)

Cholesterol

  • This is absorbed in the diet (carnivorous diet) or synthesized in the liver, and is excreted in bile, partly as cholesterol (unchanged) and partly as bile acids and bile salts. (B600.6.w6, B460.4.w4, J29.16.w6)
  • In rabbits, cholesterol is higher in does than in bucks, and shows diurnal variation, being highest in late afternoon. (B600.6.w6, J213.2.w3)
  • Serum cholesterol rises after a meal containing high levels of fats. (B460.4.w4)
  • A fasting sample should be taken; this is difficult to get in rabbits due to caecotrophy. (B600.6.w6)
    • In general, plasma cholesterol levels may change by 2 - 3 mmol/L related to feeding. (B460.4.w4)
  • Abnormal cholesterol levels may indicate hepatic impairment. (B600.6.w6)
  • Low cholesterol is an indicator of hepatic failure, chronic malnutrition or pregnancy. (J29.16.w6)
  • Increased cholesterol may occur associated with hepatic disease, raised cortisol and low circulating thyroid hormone. (J213.2.w3)
  • Hypercholesterolaemia in an anorectic rabbit suggests end-stage Hepatic Lipidosis in Rabbits, with a poor prognosis. (J29.16.w6)
  • Note: familial hypercholesterolaemia is seen in some rabbit breeds, e.g. the Watenabe rabbit. (J213.2.w3)

Triglycerides

  • Lipaemia can be seen in anorectic rabbits with Hepatic Lipidosis in Rabbits. (B600.6.w6)
  • Serum triglycerides rise after a meal containing high levels of fats. (B600.6.w6)
  • Abnormal serum fatty acids may indicate hepatic impairment. (B600.6.w6)
  • Experimentally, increased triglycerides have been seen in rabbits with induced chronic renal failure. (B600.6.w6)

Bile acids

  • These are derived from cholesterol. (B600.6.w6)
  • Usually a fasting sample should be taken (B460.4.w4); this is not practical in the rabbit. (B600.6.w6)
  • Circadian rhythm in rabbits. (B600.6.w6)
  • Fasting serum bile acid concentrations may be increased markedly associated with hepatic impairment. (B600.6.w6)
  • Have been found to be high in rabbits with Hepatic Coccidiosis in Lagomorphs (100 mol/L versus under 40 mol/L usual in normal rabbits). (B600.6.w6)

J213.2.w3

Bilirubin

Liver function tests - Bromosulphophthalein (BSP) and indocyanine green (ICG) dye tests

  • Normal BSP clearance by the rabbit, 1.8 mg/min/kg. (B614.7.w7)
  • Increased BSP retention occurs when more than 55% of the functional mass of the liver has been lost due to fibrosis or atrophy. (B601.4.w4)
  • Not a valid test in the presence of biliary obstruction. (B601.4.w4)
  • BSP may be falsely elevated in shock, dehydration or the presence of some competitive drugs. (B601.4.w4)
  • ICG clearance: exponential rate of clearance; increasing half-life with increasing dose: (B601.4.w4)
    • Dose 32 mg/min, half-life seven minutes, clearance 10% per minute over 32 minutes.
    • Dose 16 mg/kg, half-life 3.5 minutes, clearance 20% per minute over 32 minutes.
    • Dose 8 mg/kg, half-life 1.5 minutes, clearance 46% per minute.

Cortisol

  • Increased in stress, including stress caused by transportation. (J495.40.w4)
  • Increased in wild rabbits (Sylvilagus floridanus - Eastern Cottontail) sampled following collection by trapping (average about 8 g/100 mL) or falconry (average about 4.5 g/100 mL), compared to shooting (under 2 g/100 mL). (J1.21.w11)
Electrolytes
  • There may be differences in normal serum electrolyte concentrations between different breeds of rabbit. (B611.3.w3)

Calcium

  • Total plasma calcium is high compared to other mammals. (B601.4.w4, B614.7.w7, J4.194.w4, J60.13.w2)
    • Concentrations have been reported as:
      • Mean 3.2 - 3.7 mM (full range 12.8 - 14.6 mg/dL) from a compilation of eight references;
      • 2.53 - 3.68 mM (10.1 - 14.7 mg/dL), mean +/- SD 3.20 +/- 0.26 mM (12.8 +/- 1.04 mg/dL) for one group of 34 New Zealand white rabbits;
      • 2.90 - 3.95 mM (11.6 - 15.8 mg/dL), mean 3.47 +/- 0.04 mM (13.9 +/- 0.62 mg/dL) for another group (72 rabbits).

      (J4.194.w4)

      • 12 - 13 mg/dL. Note: high levels of serum calcium have also been recorded in lagomorph species other than domestic rabbits, including cottontails ( Sylvilagus sp.) and pikas (Ochotona sp.). (B614.14.w14)
  • Rabbits show high absorption of calcium from the gut and then excrete excess calcium via the kidneys. (J29.16.w6)
  • Total serum calcium may be affected by serum protein or albumin concentrations, and whether the sample was from a fed versus a fasted rabbit. (J4.194.w4)
  • Blood calcium is normally relatively low (<14 mg/dL) in growing rabbits and pregnant does. (J29.16.w6)
  • Note: most laboratories test for total calcium. Ionized calcium is a more useful measure, but more difficult (and expensive) to measure. (J29.16.w6)
  • It is preferable for each laboratory to build up its own normal reference range, then compare samples against that range. (J4.194.w4)
  • Mean fractional excretion of calcium in rabbits is 44.9% (B614.7.w7) 45-60% (J29.16.w6) (versus under 2% in most mammals). (B614.7.w7, J29.16.w6)
  • Rabbits have a similar ionized calcium fraction to other mammals. (B601.4.w4)
  • Hypercalcaemia may be seen in:
  • Hypocalcaemia may be seen with hypoalbuminaemia, diarrhoea and renal hyperparathyroidism. (J29.16.w6, J213.2.w3)
  • Hypocalcaemia may be noted in rabbits anaesthetised with halothane. (J213.2.w3)
  • Hypocalcaemia and associated tetany has been seen in lactating does. (B600.6.w6, J29.16.w6)

Phosphorus

  • Breed and sex variations have been reported. (B614.7.w7)
  • Phosphorus is falsely elevated in samples which are haemolysed. (J60.13.w2)
  • Hyperphosphataemia may occur with pre-renal, renal or post-renal failure of kidney function. (J29.16.w6)
    • Can be increased with renal insufficiency. (J213.2.w3, J60.13.w2)
      • Usually indicates chronic renal failure with loss of > 80% of nephrons. (J29.16.w6)
    • May also occur with soft tissue trauma. (J29.16.w6)
  • Hypophosphataemia may indicate dietary deficiency or reduced intestinal absorption. (J29.16.w6, J60.13.w2)

Sodium

  • Hypernatreamia may be due to water deprivation or loss of low-sodium fluids from the body (e.g. with burns, diarrhoea, peritonitis, myiasis). (B600.6.w6, J29.16.w6)
  • Hyponatreamia may be associated with chronic renal failure, inability to concentrate urine and loss of effective sodium/potassium exchange in the renal tubules. (B600.6.w6, J29.16.w6)
  • Artefactual increase with lipaemia or hyperproteinaemia. (J29.16.w6)

Potassium

  • Hyperkalaemia may be due to:
    • Acute renal failure or obstruction of urine flow. (J29.16.w6)
    • Severe tissue damage (dispersal of potassium from tissues into the extracellular space). (J29.16.w6)
    • In metabolic acidosis, due to increased exchange of potassium ions across the cell membrane. (J29.16.w6)
    • Artefacturally with samples left too long (hours) before separation of serum, or with haemolysis. (B460.4.w4, B603.2.w2, J29.16.w6)
  • Hypokalaemia may be due to:
    • Dietary deficiency of potassium, loss of potassium from the GIT, diuresis, use of intravenous fluids not containing sufficient potassium, or alkalosis (causing redistribution of potassium and sodium across cell membranes). (B600.6.w6)
    • With hyperproteinaemia or lipaemia. (J29.16.w6)
    • Stress-induced increases in catecholamines. (J29.16.w6)
    • Note: low values may be seen with some anaesthetics such as pentobarbitone. (B600.6.w6)
    • Note: Hypokalaemia results in muscle weakness and depression. (B600.6.w6) See: Hypokalaemia in Rabbits
Enzymes

Sensitivity and specificity of serum enzymes as indicators of disease

  • The specificity of a given enzyme as an indicator of disease or injury of a specific tissue/organ depends on the concentration of the enzyme in that organ/tissue (in comparison to the concentration in other organs) and whether the enzyme, released from that tissue/organ reaches the blood. (B601.4.w4)
  • The sensitivity of a serum enzyme as an indicator of injury/disease depends on the duration of elevation of the enzyme in serum. The half-life of the enzyme in serum is affected by the rate at which it decomposes and/or is removed from the blood. (B601.4.w4)
  • There is no single commercial assay useful as an indicator of liver damage in rabbits. (J213.2.w3)
  • Note: "Haemolysed samples are unsuitable for enzyme estimation as enzymes released from the red cells are liable to interfere with the assay." (B460.4.w4)

Alanine aminotransferase (ALT) / Glutamic pyruvic transferase (GPT)

Aspartate aminotransferase (AST)/serum glutamate transaminase (SGOT)

Alkaline phosphatase (ALP, AP)

  • Highest levels in the intestinal mucosa and in the kidneys. (B601.4.w4)
  • In the liver and kidney of rabbits there are two ALP isoenzymes, from two different genes (B600.6.w6, B601.4.w4, B614.7.w7); there is also an intestinal form. (B600.6.w6, B614.7.w7)
  • In rabbit liver, this enzyme is found in the greatest quantities in membranes bordering the bile canaliculus. (B601.4.w4)
  • Normally, rabbit serum ALP is derived from bone, liver and intestine, as well as from the placenta in pregnant does. (B601.4.w4)
    • In rabbits, ALP falls in pregnancy. (B614.7.w7)
    • In young, growing rabbits, ALP may be raised due to normal osteoblastic activity. (J29.16.w6)
  • ALP does not generally rise due to liver necrosis, but may increase associated with bile stasis, since production of ALP is increased due to the increased level of bile acid. (B601.4.w4, J29.16.w6)
    • ALP increases with biliary obstruction (e.g. associated with neoplasia). (B600.6.w6)
    • ALP increases with experimental bile duct ligation. (B614.7.w7)
    • ALP may rise with liver abscess, neoplasia, hepatic coccidiosis or lipidosis leading to bile stasis. (J29.16.w6)
    • ALP may rise with extrahepatic abscess or neoplasia obstructing the bile duct. (J29.16.w6)
  • ALP may increase in young rabbits (e.g. two-months old) with Hepatic Coccidiosis in Lagomorphs. (B614.7.w7)
  • Increases with fractures and other bone lesions. (J29.16.w6, J213.2.w3)
  • ALP also can rise with enteric disease. (B600.6.w6)
  • May decrease in pregnant rabbits and with diarrhoea. (J213.2.w3)
  • Note: does not rise with restraint, therefore may assist in determining whether rises of other enzymes are due to liver disease or restraint. (J29.16.w6)

Creatine kinase (CK)/Creatine phosphokinase (CPK)/Creatinine kinase

  • Creatine kinase is found particularly in skeletal muscle (CK-MM), brain (CK-BB), heart (CK-MB) and in mitochondria (CK-Mt). In rabbits, the main forms in the peripheral circulation are CK-MM and CK-BB. (B614.7.w7)
  • Raised CK indicates muscle degeneration; (B614.7.w7,J213.2.w3) and is considered "a rapid and sensitive indicator of muscle degeneration in rabbits." (B614.7.w7); for example it is raised following surgery. (B601.4.w4)
    • CK may be raised associated with the process of blood collection, e.g. in samples collected by cardiac puncture (B614.7.w7) or if the rabbit struggles during restraint. (J29.16.w6)
    • CK may be increased associated with anaesthesia, and even more in hypothermic anaesthetised rabbits. (B614.7.w7)
  • This enzyme has a short half-life and returns to normal rapidly if the insult causing the rise is not continued. (B460.4.w4)
  • CK may be increased with haemolysis. (B603.2.w2)

Lactate dehydrogenase (LDH)

  • Present in most cells, including erythrocytes, at higher concentrations than in plasma. (B601.4.w4, B614.7.w7)
  • Increased with haemolysis e.g. due to poor sample handling. (B601.4.w4, B614.7.w7)
  • Not sufficiently specific for use in rabbit medicine. (B601.4.w4, J29.16.w6)
  • LDH may be increased with haemolysis. (B603.2.w2)

Gamma glutamyltransferase (GGT)

  • In rabbits, mainly in renal epithelium; lower activity in the liver, where it is mainly found in the epithelial cells of bile ducts. (B614.7.w7)
  • Low in neonates, but rapidly reaches the same values as in adults. (B614.7.w7)
  • Less sensitive indicator than in other species. (J29.16.w6)
  • Increased GGT:

Glutamate dehydrogenase (GDH)

  • Mitochondrial enzyme, mainly in the liver, heart and kidney with less in the brain, skeletal muscle and leucocytes. (B614.7.w7)
  • Within the liver, GDH is mainly found in centrilobular cells; raised GDH might therefore suggest liver damage with a centrilobular pattern (unlike ALT). (B614.7.w7)

Amylase

  • In rabbits, high concentrations are present in pancreatic tissue and lower concentrations in salivary glands; it is also produced by caecal microorganisms. (B600.6.w6, B614.7.w7, J29.16.w6)
  • Rabbits have a relatively low normal serum amylase concentration. (B600.6.w6)
  • Serum amylase may increase with:
    • Obstruction of the pancreatic duct or with pancreatic disease. (B600.6.w6, B614.7.w7, J29.16.w6, J60.13.w2)
    • Rabbits with pancreatitis. (B601.4.w4, J29.16.w6)
    • May also be increased with renal disease (since amylase is cleared by renal filtration) or corticosteroid treatment. (B601.4.w4, J29.16.w6, J60.13.w2)

Lipase

  • Possibly useful in diagnosis of pancreatitis. (B601.4.w4)
  • Artefactually elevated by use of corticosteroids. (J29.16.w6)
Associated techniques linked from Wildpro

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Urinalysis

Urinalysis is used for assessment of the rabbit's urinary system and other body organs/systems. (B601.4.w4, P113.2005.w2)
  • Urinalysis should take place as soon as possible after collection of the sample; if necessary the sample may be refrigerated and examined within 2 - 3 hours. (B601.4.w4) 
    • Urine samples for cytology or sediment examination should not be refrigerated or frozen. (B460.6.w6)
  • Note: Dipsticks are useful for evaluation of blood, glucose, ketones and pH, but are not useful for accurate measurement of other parameters (e.g. specific gravity) of rabbit urine. (J29.16.w6, J60.13.w2)
  • A refractometer should be used for measuring urine specific gravity. (B601.4.w4, J29.16.w6)
Urine collection

Urine may be collected in several ways:

  • Voided sample
    • A urine sample may be collected from house-trained rabbits (and also many hutch rabbits) by placing a clean, empty litter box in the site where the animals usually urinates. (B600.3.w3, B601.2.w2)
      • Alternatively, cleaned aquarium gravel or non-absorbable veterinary medical litter can be added to the litter box. (B615.6.w6)
      • A free catch sample from a clean litter tray is relatively easy to obtain. (J29.16.w6)
      • Or the sample may be intercepted - a "free catch" sample (rabbit permitting), preferably avoiding the first part of the urine stream which will include exudate from the urethra and, in does, the vaginal vestibule. (B601.4.w4)
    • A urine sample collected by this method should not be used for culture and sensitivity because the sample will be contaminated. (B601.2.w2)
    • This is suitable for:
      • Urinalysis when contamination of the sample is not a problem, e.g. when culture and sensitivity is not being performed.
      • Where other urine collection techniques are not possible due to costs, difficult animal, sedation/anaesthetic risks etc.
  • Manual expression of the bladder.
  • Cystocentesis
  • Uretheral catheterisation
Normal urine values
  • Daily urine production is 20 - 350 mL/kg, normal about 130 mL/kg. (B611.3.w3, B614.7.w7, J213.2.w3)
  • Maximum concentrating ability about 1.9 osmoles/L. (B611.3.w3)
  • Rabbit urine is:
    • Alkaline (pH 8.2) (B611.3.w3, J72.49.w1, J213.2.w3, P113.2005.w2); pH 8 - 9 (P113.2005.w1); pH 8.2 - 9 (B606.7.w7); pH 7.60 - 8.80 (B614.7.w7); 7.5 - 9. (J29.16.w6, J60.13.w2)
    • Specific gravity of 1.003 - 1.036. (B606.7.w7, J213.2.w3, P113.2005.w2) 1.003 - 1.036, average 1.015. (B614.7.w7, J29.16.w6, J60.13.w2)
      • This can be measured accurately from a drop of urine using a refractometer. (B601.4.w4)
      • Dipsticks are less useful. (J29.16.w6)
    • Generally white to yellow in colour but may be orange to red-brown due to porphyrin pigments from plants. (B601.4.w4, J29.16.w6, J60.13.w2, J72.49.w1, P113.2005.w1, P113.2005.w2)
    • Usually turbid. (J60.13.w2, J72.49.w1)
  • A trace of protein may be present in urine from normal rabbits. (B601.4.w4, B611.3.w3, P113.2005.w2)
    • In young rabbits there may be a trace of albumin. (B601.4.w4, B606.7.w7, J213.2.w3)
  • A trace of glucose may be present in urine from normal rabbits. (B606.7.w7, B611.3.w3, P113.2005.w2)
  • Sediment should contain few or no epithelial cells and bacteria and no casts; a few leucocytes and erythrocytes may be found occasionally. (B600.6.w6, B606.7.w7, B611.3.w3, J213.2.w3)
    • Up to three cells per high power field may be considered normal. (B601.4.w4)
  • Crystals are usually present in large quantities - calcium carbonate monohydrate, anhydrous calcium carbonate and less commonly ammonium magnesium phosphate (triple phosphate, struvite). (B600.6.w6, B606.7.w7, B611.3.w3, B614.7.w7, J60.13.w2, J213.2.w3)
    • Oxylate crystals may be present. (B600.6.w6)
Abnormal findings
  • Ketones 
  • Brown colouration may indicate the presence of myoglobin or methaemoglobin - but may also occur with plant pigments. (B601.4.w4)
  • Cloudy urine may be due to the presence of calcium (normal), white and red blood cells, bacteria, mucus or epithelial cells. (B601.4.w4)
    • WBC are not found in normal urine (B601.4.w4); low numbers may be normal. (B600.6.w6)
    • Casts are an abnormal finding. (B601.4.w4)
    • Bacteria should not be present in normal urine. (B601.4.w4)
  • Micro-urinary calculi
    • Large amounts of fine calculi, often called "sludge", is abnormal. (B601.4.w4)
      • This must be distinguished from the normal calciuria of rabbits on a high-calcium diet. (B601.4.w4)
      • If a urine sample is centrifuged then shaken, normal crystals will resuspend, while sludge will remain as a mass. (J29.16.w6)
  • Clear urine:
    • May be seen in pregnant, lactating or young rabbits. (B600.6.w6, J34.17.w2, J72.49.w1)
    • In anorectic rabbits. (B600.6.w6)
    • Associated with acidosis. (J34.17.w2, J72.49.w1)
  • Low pH
  • Bilirubin is rarely found in rabbit urine but may be present following destruction of haem from either rbc or muscle. (B601.4.w4)
  • Haematuria
  • Glucose
    • Is not usually present.
    • Trace to moderate amounts may be found after a painful or frightening experience, and with some chronic stresses such as pain, as well as in rabbits stressed by handling or transport. (B601.4.w4, J15.23.w3)
      • Preferably test a sample collected from the rabbit in its home environment. (J15.23.w3)
    • Diabetes Mellitus in Rabbits (J45.109.w1); this is rare in pet rabbits, although it is recognised in New Zealand white laboratory rabbits as a hereditary disease. (B600.6.w6, B601.4.w4, J15.23.w3, J45.109.w1)
    • Glucosuria occurs in rabbits with anorexia, hepatic lipidosis and ketosis (see: Hepatic Lipidosis in Rabbits).(J15.23.w3)
  • Protein
    • Increased with renal damage. (B601.4.w4, J13.19.w1)
    • Transient proteinuria may occur after excessive muscular activity, seizure, or with stress. (B601.4.w4)
    • Consider protein levels in association with urine specific gravity - protein present in very dilute urine is more likely to be significant than the same level of protein in concentrated urine. (B601.4.w4, J29.16.w6)
    • Proteinuria (more than a trace, which is normal particularly in young rabbits) is an early sign of renal disease. (J29.16.w6)
  • Specific gravity:
    • Fixed urinary specific gravity (1.008 - 1.012 together with dehydration and raised serum creatinine/BUN or abnormally high PCV indicates poor renal function. (B601.4.w4)
    • Raised SG (> 1.030), i.e. concentrated urine is seen with prerenal azotaemia. (J29.16.w6, J60.13.w2)
    • Dilute urine (SG < 1.013) plus azotaemia is seen in renal failure. (J29.16.w6, J60.13.w2)
    • Measure with a refractometer; this is more accurate than a dipstick test. (J29.16.w6)
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Cerebro-spinal Fluid

  • Collection of cerebrospinal fluid (CSF) can be useful in the differential diagnosis of neurological (CNS) disease. (B600.3.w3, B602.14.w14, P113.2005.w2)
    • Culture may be useful for diagnosis of Listeriosis. (J213.2.w3)
    • Glucose, cell counts and differential cell counts must be done immediately. (B601.4.w4)
    • Other testing may be carried out immediately or following refrigeration. (B601.4.w4)
CSF collection
Normal rabbit CSF constituents
  • WBC total 0 - 7 cells/mm, median 3 cells/mm (data from 48 New Zealand white rabbits). (J213.2.w3, J495.32.w3)
  • Lymphocytes 40 - 79% (median 67%) (data from 48 New Zealand white rabbits; mainly T-lymphocytes). (J213.2.w3, J495.32.w3)
  • Monocytes 21 - 60% (median 33%) (data from 48 New Zealand white rabbits). (J213.2.w3, J495.32.w3)
  • Glucose 75 mg/dL. (B611.3.w3, J213.2.w3); 56 - 135 mg/dL mean +/- SD 78 +/- 13 mg/dl (J83.14.w1)
  • Urea nitrogen 20 mg/dL. (B611.3.w3, J213.2.w3)
  • Creatinine 17 mg/dL. (B611.3.w3, J213.2.w3)
  • Cholesterol 33 mg/dL. (B611.3.w3, J213.2.w3)
  • Total protein 59 mg/dL. (B611.3.w3, J213.2.w3) 16 - 66 mg/dL, mean +/- SD 33 +/- 10 mg/dL. (J83.14.w1)
  • Alkaline phosphatase 5.0 IU/dL. (B611.3.w3, J213.2.w3)
  • Carbon dioxide 41.2 - 48.5 mL%. (B611.3.w3, J213.2.w3)
  • Sodium 149 mEq/L. (B611.3.w3, J213.2.w3)
  • Potassium 3.0 mEq/L. (B611.3.w3, J213.2.w3)
  • Chloride 127 mEq/L. (B611.3.w3, J213.2.w3)
  • Calcium 5.4 mg/dL. (B611.3.w3, J213.2.w3)
  • Magnesium 2.2 mEq/L. (B611.3.w3, J213.2.w3)
  • Phosphate 2.3 mg/dL. (B611.3.w3, J213.2.w3)
  • Lactic acid 1.4 - 4.0 mg/dL. (B611.3.w3, J213.2.w3)
  • Non-protein nitrogen 5.6 - 16.8 mg/dL. (B611.3.w3, J213.2.w3)
Abnormal findings
  • Bright red - usually indicates contamination with blood at the time of collection. (B601.4.w4)
  • Dull dark red-brown - suggests intracranial haemorrhage (trauma or disease). (B601.4.w4)
  • Increased turbidity - may be increased cells (bacterial meningitis). (B601.4.w4)
  • Note: no single parameter can be used as a dependable indicator of CNS disease. (B601.4.w4)
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Bone Marrow 

Bone marrow aspiration is used to collect a sample for cytology; bone marrow biopsy is used to collect a sample for histopathology.
  • If samples are needed for both cytology and histopathology, obtain the sample for cytology first (via the bone marrow aspiration technique). (B601.2.w2)

Examination of bone marrow aspirates may be expected to find:

  • 6.5 +/- 2.4% proerythroblasts, myeloblasts, undifferentiated blasts and lymphocytes.
  • 14.5 +/- 4.4% dividing precursors - basophilic erythroblasts, promyelocytes and myelocytes;
  • 81.5% +/- 4.8% late precursors and mature cells.

(B614.7.w7)

  • The myeloid:erythroid ratio is about 1:1 in adults. (B461.170.w170)
    • In newborn rabbit kits, erythroid cells made up 31 - 55% of cells, dropping in some individuals by the second day, but around the 75 - 80% level on day four to seven, followed by a gradual decline to about 50% by three to four weeks of age. Myeloid cells at birth represented under 40% of cells, dropped irregularly to about 15% in the latter half of the first week of life, then increased gradually to about 50% by three to four weeks of age. Primitive cells made up about 10% of cells at birth, declined rapidly to very low levels (0.3%) by seven days, increased again to about 3 - 4% at two to three weeks but then declined again to under 2%. (J494.64.w1)
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Faecal Analysis

Faecal analysis is useful for detection of helminth and protozoal infections, and for investigation of gastrointestinal disease which is not responding to therapy. (J72.49.w1)

Faeces versus caecotrophs

It is important to be able to distinguish between the hard faecal pellets which lagomorphs produce and the softer caecotrophs which they generally eat directly from the anus.

  • Caecotrophs: Small particulates and a wide range of microorganisms - bacteria, yeasts and protozoans. (B600.6.w6, B601.8.w8)
  • Hard faeces: indigestible large particulates (plant fragments). (B600.6.w6)
  • Diarrhoea: There may be a mixture of small and large (> 5.0 mm) particles with fluid and mucus. (B600.6.w6, B601.8.w8)
    • This is due to a failure of the normal mechanisms for separating the digestible from the indigestible particles. (B600.6.w6)
  • Note: Passalurus ambiguus eggs and coccial oocysts may be found in both hard faeces and caecotrophs. (B600.6.w6)
Worm egg counts
A wide range of nematodes can be found in wild lagomorphs, also cestodes and trematodes. In domestic rabbits, Pinworm Infection is most common but is often asymptomatic. 
  • Helminth eggs can be detected on a direct smear (faecal wet mount) or by faecal flotation. (B609.2.w2, J29.5.w1, J213.9.w4)
  • Faecal flotation: (B609.2.w2, J29.5.w1, J213.9.w4)
    • Mix the faecal sample with saturated salt or saturated sugar solution.
    • Centrifuge.
    • Fill the container to the brim with the salt or sugar solution.
    • Place a cover slip over the meniscus of the liquid and leave for a few minutes.
    • Remove the cover slip and place on a microscope slide.
    • Examine under the microscope.

    (B600.17.w17, V.w131)

  • Some of the more common species include:
Coccidia
  • These may be found in both hard faeces and caecotrophs, (B600.6.w6)
  • It is important to remember that coccidial oocysts may be found in faeces of rabbits which are clinically normal. (J72.49.w1)
  • There are a number of species of coccidia which can parasitise rabbits and other lagomorphs. The initial distinction to be made is between Eimeria stiedae, which parasitises the liver, and other species, which are found in the intestines.
    • Oocysts of Eimeria stiedae (Hepatic Coccidiosis in Lagomorphs) are ovoid to ellipsoid, 36.9 x 19.9 m (range 28 - 40 x 16 - 25 m). The oocyst wall is smooth and yellowish-orange to salmon coloured; it has a distinct micropyle. (B24)
    • Oocysts of intestinal coccidia (Intestinal Coccidiosis): depending on the species of coccidia involved, these vary from about 15 to 40 m long. The size, shape, colour of the oocyst wall and presence or absence of a micropyle can assist in identification of coccidial species. (B24, B609.2.w2)
  • Must be distinguished from the non-pathogenic budding sporogenous yeast, Saccharomyces. (B600.6.w6)
Abnormal bacteria
  • Escherichia coli may be found in large numbers in rabbits with diarrhoea due to Colibacillosis. (B600.6.w6)
    • Small numbers may not be significant. (V.w131)
  • Clostridium spiroforme (large, Gram-positive, semi-circular or spiral) may be found and may indicate Clostridial Enteritis and Enterotoxicosis in Rabbits. However, demonstration of the associated toxin is needed to confirm clostridiosis. (B600.6.w6)
    • In patients with clinical disease there are usually large numbers of large Gram-positive endospore-producing bacteria in the faeces. (B609.2.w2)
    • The presence of low numbers of Clostridial organisms in the faeces is not abnormal. (B600.6.w6)
  • Salmonella may be found (Salmonellosis). (B600.6.w6)
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Serological Tests

Serological tests are available in some countries (variable availability between countries) for:

  • Encephalitozoon cuniculi (Encephalitozoonosis in Lagomorphs) - available in the UK 
    • A negative test enables Encephalitozoon cuniculi infection to be ruled out as the cause of neurological disease, since antibodies are detectable before brain lesions develop due to infection with this organism. (J29.16.w6)
    • A positive test confirms exposure; it does not confirm that any particular clinical signs are due to Encephalitozoon cuniculi infection; detection of both IgM and IgG suggests recent infection). (B600.6.w6)
  • Myxomatosis - available in the UK
  • Pasteurella multocida infection (Pasteurellosis in Lagomorphs) - available in the USA (serology and PCR).
    • A single positive titre is not diagnostically useful as the organism may be present in the nasal cavities without associated illness, or the rabbit may have been infected previously.
    • A rising titre (samples two weeks apart) may be useful. (J29.16.w6)
    • Rabbits under two months old may still have maternal antibodies, therefore interpretation of results is difficult. (J29.16.w6)
  • Toxoplasma gondii (Toxoplasmosis in Waterfowl and Lagomorphs (with notes on Hedgehogs, Elephants and Bears))) - available in the UK
  • Treponematosis in Lagomorphs - available in the UK
  • Viral haemorrhagic disease (Rabbit Haemorrhagic Disease) - available in the UK
  • Cryptosporidium spp. (Cryptosporidiosis in Mammals) - ELISA can be used to assess exposure. (B529.15.w15)

(B600.6.w6, J29.16.w6, J495.32.w6)

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Skin Testing

The rabbit should be restrained in sternal recumbency on a non-slip surface such as a rubber mat on the table, with its eyes and rump covered, while skin samples are taken. (J72.49.w1)
  • Skin scrapings cleared with potassium hydroxide solution can reveal ectoparasites. (J72.49.w1)
  • Staining of skin scrapings with lactophenol can reveal fungal elements. (J72.49.w1)
Flea combing
Skin scraping
Cellophane/Acetate tape method
Fine needle aspirate 
  • Technique
    • Carefully clip and clean the lesion. (B601.13.w13)
    • Select an adequate sized needle because the exudate may be thick. (B601.13.w13)
      • 21 gauge needle. (B601.13.w13)
      • 22 gauge or larger needle. (B602.18.w18, B609.2.w2)
    • Attach a small syringe to the needle, e.g. 5 mL syringe, and insert the needle into the middle of the lesion. Draw back on the syringe plunger to obtain a sample. If a sample is not obtained it may be necessary to reposition the needle in the lesion and try again.
    • Either send off the sample for culture and sensitivity or make a smear of the sample on a microscope slide and view under microscopy.
  • Indications
Wood's lamp examination 
  • Technique
    • Allow the lamp to warm up prior to use (B601.13.w13)
      • A minimum of five minutes is recommended. (B609.2.w2, J213.6.w1)
    • Perform the test in a dark room. (B601.13.w13)
    • The lamp needs to be exposed to the suspicious lesion for several minutes. (B609.2.w2, J213.6.w1)
    • A true positive reaction (that is associated with Microsporum canis) is an apple-green fluorescence at the base of the hair shafts. (B609.2.w2, J213.6.w1)
    • False-positive fluorescence is quite common and will appear white or blue in colour; this may occur due to debris, scales, bacteria or keratin associated with epidermal sebum on skin and hair. (B609.2.w2, J213.6.w1)
  • Indications
    • Ringworm - Microsporum canis only (B601.13.w13); however, only around 50 % of strains will fluoresce. (B604.5.w5, J213.6.w1)
      • Many pathogenic dermatophytes (including the most common dermatophyte in rabbits: Trichophyton mentagrophytes) do not fluoresce so this is not a particularly useful screening tool. (B600.9.w9, B602.19.w19, B609.2.w2)
Bacterial culture 
  • Technique
    • A sterile, deep sample should be taken from the affected tissue and/or from the exudate. (B602.18.w18, B609.2.w2)
    • The sample may be obtained by swab, fine needle aspirate, skin scrapings or biopsy.
    • Samples should be cultured for aerobic and anaerobic bacteria and then the antibiotic therapy should be based on the sensitivity results. (B602.19.w19, B609.2.w2)
    • Note:
      • In cases of abscessation, the wall or capsule should be sampled because bacteria that are deep within the exudate are frequently nonviable. (B606.4.w4, B609.2.w2)
      • It is common to get lack of growth, particularly with anaerobic infections or a fastidious bacterial infection. (B602.18.w18, B609.2.w2)
  • Indications
Fungal culture 
  • Technique
    • Pluck hairs from the edge of an alopecic lesion. It is best not to use a random pattern. (B609.2.w2) Take plenty of hairs for an adequate sample. (B601.13.w13)
    • Alternatively, the entire body can be brushed with a sterile toothbrush or surgical scrub brush and the brushings (hair and cellular debris) are then cultured (Mackenzie's toothbrush technique). (B600.9.w9, B604.5.w5, J3.146.w2)
  • Indications
    • Ringworm including Trichophyton mentagrophytes and Microsporum canis. (B601.13.w13)
Skin biopsy
  • Technique
    • Sedation or general anaesthesia is usually required for this procedure. (B601.13.w13)
    • To biopsy a lesion in the conscious rabbit, use a topical preparation containing Prilocaine and Lidocaine (EMLA cream) as a local anaesthetic. (B600.9.w9)
    • Carefully clip and prepare the lesion.
    • Use a scalpel blade or punch biopsy tool to obtain the sample and then suture if necessary.
    • The sample should contain both abnormal and normal tissue in the same specimen. (B609.2.w2)
  • Indications
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Microbiological Investigation

  • Ideally, choice of antibiotics should always be based on culture and sensitivity testing.
    • It is particularly important to test samples when initial therapy has been unsuccessful. (J72.49.w1)
  • The API system can be used in the identification of microorganisms. (J72.49.w1)
  • Microbiological investigation is also useful as an adjunct to post mortem examination. (J72.49.w4)
  • In examination for intestinal organisms, testing for bacteria is not likely to be useful if the rabbit has been dead for more than 24 hours. (J72.49.w4)
  • For isolation and identification of Salmonella, enrichment media are useful. (J72.49.w4)
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Cytological Investigation

In addition to blood, bone marrow, urine and CSF, cytological investigation can be carried out on samples obtained from the live rabbit by abdominocentesis, thoracocentesis, brochoalveolar lavage or fine needle aspirate from organs or lesions.
  • Synovial fluid can be aspirated if septic arthritis is suspected. With septic arthritis, the fluid may be turbid, with an increased leucocyte count (mainly neutrophils), and bacteria free in the fluid or within neutrophils. (B609.2.w2)
  • At necropsy, impression smears can be taken from a wide variety of organs, particularly liver, lung, kidney, lymph nodes and gastrointestinal mucosa. (B600.10.w10, J72.49.w4) These are useful for detection of coccidia (Intestinal Coccidiosis in Hedgehogs and Lagomorphs, Hepatic Coccidiosis in Lagomorphs), toxoplasma (Toxoplasmosis) etc.
    • For detection of Clostridium piliforme (Tyzzer's Disease in Lagomorphs) in the liver at necropsy, impression smears stained with Giemsa or the Warthin Starry technique are useful. (J72.49.w4)
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Authors & Referees

Authors Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Frances Harcourt-Brown BVSc FRCVS (V.w140); Petra Wesche DVM MSc MRCVS (V.w131)

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