Marginal ear vein/artery

Technique

Removal of blood from the marginal ear vein or artery is one of the most common and least invasive methods of talking blood from a rabbit. This technique can be used with all strains and for single and repeat samples. Use of the artery is normally used for larger volume samples or for arterial blood, but carries a greater risk of haematoma and bruising.

Slides and video for sampling from the central ear artery are available on the website of the Norwegian Reference Centre for Laboratory Animal Science and Alternatives.

The rabbit should be restrained and it can be helpful to wrap the animal in a large cloth to avoid inadvertent movement. Restraint can cause stress, therefore the duration of restraint should be minimised. Blood is taken from the tip of the ear, away from the base of the ear. Serial blood samples can be taken by moving towards the base of the ear on the same vein and by alternating ears. The ear should be warmed in order to dilate the vessel. This can be done by gently stroking; it should not be necessary to use a heat lamp. The technique should be carried out aseptically and the dorsal surface of the ear should be shaved or clipped. The fur should not be plucked. Local anaesthetic cream  (e.g. EMLA cream) can be applied to the site 30 minutes prior to blood sampling. The vein is normally occluded distally (away from the animal) before the needle is inserted.

Depending on the size of the rabbit and the frequency of sampling, 0.5 - 10 ml of blood can be collected. Up to eight samples can be collected in any 24-hour period, depending on sample volume and scientific justification. In order to minimise damage to the ear the number of attempts to take a blood sample should be minimised (no more than three needle sticks in any one attempt).

Blood flow should be stopped before the animal is returned to its cage or pen by applying finger pressure on soft tissue placed at the blood sampling site for approximately two minutes.

Summary

Number of samples Up to eight samples may be taken in any 24-hour period, depending on sample volume.
Sample volume Up to 0.5 - 10 ml, depending on the size and strain of the rabbit.
Equipment 19G - 23G butterfly needle, depending on the strain and size of the rabbit.
Staff resource Two people: one to restrain the rabbit and the other to take the blood sample.
Adverse effects
  • Bruising/haemorrhage <1%
  • Infection <1%

Resources and references

  • A good practice guide to the administration of substances and removal of blood, including routes and volumes. 
  • Elizabeth A et al. (2010), A jugular bleeding technique in rabbits. Lab Animal Europe. Vol. 10 No. 2,  pp pp.24-31
  • Ness RD (1999), Clinical pathology and sample collection of exotic small animals. The Veterinary Clinics of North America: Exotic Animal Practice. 2(3),  pp 591-620
  • Benson KG, Paul-Murphy J (1999), Clinical pathology of the domestic rabbit: Acquisition and interpretation of samples. Veterinary Clinics of North America, Exotic Animal Practice. 2(3),  pp 539-551
  • Lucas RL, Lentz KD, Hale AS (2004), Collection and preparation of blood products. Clinical Techniques in Small Animal Practice. 19(2),  pp 55-62
  • Removal of blood from laboratory animals and birds.

Marginal ear vein/artery sampling in other animals

This technique is only appropriate for use in the rabbit

All blood sampling techniques in the rabbit

Click here for information on cardiac puncture blood sampling in the rabbit