TECHNIQUE

Blood Sampling of Hedgehogs (Disease Investigation & Management)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords See also:
Description Before performing any clinical technique, the associated legal and ethical considerations should be consulted, knowledge of the potential complications/ limitations/ risk should be gained, and the level of expertise and qualification required must be ascertained.

When blood sampling a hedgehog wildlife casualty, it is important that general considerations applicable to blood sampling of all wildlife casualties be considered. (See: Blood sampling - Wildlife Casualty Assessment)

A detailed description of intravenous access is available (See: Intravenous Access (Venepuncture) of Hedgehogs) and should be consulted in combination with this page.

The following information relates directly to considerations for blood sampling of the hedgehog.

  • Blood sampling in the hedgehog has not been a frequently practised technique to date. However it is now receiving increased attention as a tool to assist with health screening and pre-release assessment of wildlife casualties.(J3.151.w2)
  • Blood sampling in the hedgehog requires general anaesthesia in the vast majority of cases. Access may be possible if the animal is unconscious or seriously injured, however in these hedgehogs the peripheral perfusion is likely to be poor and the veins collapsed.
Vein Selection:
  • Intravenous access for blood sampling may be from a number of veins, although the superficial veins of the hind limbs appear to be most commonly used.
  • The medial saphenous vein has been recommended as the vein of choice for blood sampling in the hedgehog. The hedgehog should be positioned laying on its back (dorsal recumbency) with the hind limb in extension for the sampling procedure.(J3.151.w2)
  • Intravenous access is possible via the saphenous vein running approximately in the midline along the back of the hind limb. The hedgehog can be positioned laying on its belly (ventral recumbency) with its hind limb extended.(V.w26)
  • The lateral or medial saphenous vein can be used for blood sampling (B284.6.w6); superficial veins of the hind limbs can be used.(B151)
  • The lateral saphenous, a superficial vein, can be used for intravenous access. (J60.1.w1)
    • The vein can be visualised running across the lateral aspect of the hind limb as it passes over the stifle. (B150.w1)
  • Alternate veins which can be accessed include the cephalic, jugular (B291.12.w12), femoral (B150.w1) or cranial vena cava. (B150.w1, J15.21.w1)
  • Cardiac puncture and retro-orbital sinus bleeding are techniques described in the literature which are considered by many to be ethically unacceptable. (J3.151.w2, V.w6, V.w26, V.w44)
  • Clipping a nail short has been described as a method for collecting small blood samples from hedgehogs.(B150.w1, J15.21.w1) 
    • However this amputation technique is likely to be painful and is considered by many to be ethically unacceptable. (J3.151.w2, V.w5, V.w26, V.w44)
    • In addition, the blood samples obtained have a high risk of contamination with urine, faeces or other material. (V.w26)
Technique:
  • Ensure that all equipment is available prior to starting the procedure.
  • Ensure adequate restraint of the patient; usually requires general anaesthesia for the hedgehog. (See: General Anaesthesia of Hedgehogs)
  • Carefully clip and clean the injection site and disinfect with surgical spirit.
  • An appropriate needle size (gauge and length) and syringe size should be chosen, according to the preference of the operator. 
    • A 27 gauge, 1/2 inch needle swaged on to a one millilitre syringe has been described for blood sampling in the hedgehog. (J3.151.w2)
    • A 24 gauge, five-eighths inch hypodermic needle on a one millilitre syringe may be used for intravenous access in the hedgehog. (V.w26, V.w44)
  • 'Raise' the vein by applying pressure, occluding venous return, therefore making the vein fill with blood.
  • Insert needle into the vein slowly and at a very acute angle, almost parallel to the vein.
  • Slowly fill the syringe with blood by withdrawing the syringe plunger. 
  • Too great a pressure on the syringe plunger when taking blood may cause the vein to collapse, stopping the blood flow and may damage blood cells (particularly when using a small gauge needle).
  • Release the pressure and stop raising the vein when the sample has been taken.
  • Remove needle from the vein slowly and with care.
  • Apply pressure over the venepuncture site until clotting has occurred.
  • Clean any excess blood from the area after clotting has been achieved.
Appropriate Use (?)
  • Analysis of a blood sample has been recommended as part of the pre-release veterinary check for casualty hedgehogs (B151, D92) and should be considered wherever possible.
  • Increased focus of attention is now being placed on the importance of blood sampling in the hedgehog as a method to aid in health checks and pre-release assessment. (J3.151.w2)
Notes
  • Blood sampling and testing has not been widely practised to date because of the lack of established blood sampling techniques in the hedgehog. (J3.151.w2)
  • Interpretation of blood analysis data to date has been limited by the lack of large sample size, species-specific, reference range information available. (J3.151.w2)
  • Variation of reference range data in the literature exists due to small sample sizes in some studies and variables including environmental conditions, sex and age. (J3.151.w2)
  • Further research is required to establish reference range data for hedgehogs with investigation of the importance and effect of a number of variables (e.g. ambient and body temperature, diet etc.) (J3.151.w2)
  • The minimum amount of blood required should be taken.
    • No more than 1% of the body weight of the individual should be taken at one time. (B36.6.w6)
    • A more conservative ceiling of 0.5% of the body weight of the individual at any one time is often used.
    • Blood samples of 0.5 ml have been reported to be taken from hedgehogs of over 500 g body weight. (J3.151.w2)
Complications/ Limitations / Risk
  • Venepuncture for blood sampling can be difficult in the hedgehog (J15.21.w1, B284.6.w6), particularly with small individuals.(V.w26)
  • Intravenous access can be very difficult in hedgehogs, particularly if veins are very small or collapsed.
  • The short neck and local fat deposits in the hedgehog make the jugular vein of the hedgehog less accessible when compared with other species for blood sampling.(B284.6.w6)
  • Risk of haematoma formation - associated blood loss can be significant for animals of small body weight.
  • Veins are fragile, and will accept a relatively few number of punctures.
  • Complications (haematoma, phlebitis, bruising) can be reduced through optimal venepuncture technique and vein management.
  • General anaesthesia is generally required for intravenous access in the hedgehog.
  • Requirement for physical and chemical restraint, and the stress which this may involve.
  • Care should be taken to ensure that only a safe volume of blood is taken, depending on the body weight of the hedgehog and allowing for disease or debility.
Equipment / Chemicals required and Suppliers
  • Appropriate-sized needle and syringe.
  • Appropriate anticoagulant sample tubes.
Expertise level / Ease of Use
  • Procedure should only be undertaken by an individual with appropriate clinical training and practical experience; this would usually be a veterinarian or someone with advanced veterinary technician training.
Cost/ Availability
  • Cost of disposables including needle, syringe, anticoagulant containers.
  • Cost of external laboratory work.
  • Cost of reagents and equipment for in house testing.
Legal and Ethical Considerations In some countries there may be legislation restricting the use of this type of technique to licensed veterinarians. For example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides, subject to a number of exceptions, that only registered members of the Royal College of Veterinary Surgeons may practice veterinary surgery." (See: LCofC1 - RCVS Guide to Professional Conduct 2000 - Treatment of Animals by Non-Veterinary Surgeons)

Blood cannot be taken except to benefit the health and welfare of the individual animal.

If blood is to be taken for research purposes appropriate project and personal licences are required under the Animals (Scientific Procedures) Act 1986. See: Wildlife Casualty Legislation.

Authors Becki Lawson (V.w26)
Referee Debra Bourne (V.w5), Suzanne I. Boardman (V.w6), Tiffany Blackett (V.w44)
References B36.6.w6, B150.w1, B151, B284.6.w6, J3.151.w2, D92, V.w5, V.w6, V.w26, V.w44

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