Tarsal vein

Technique

This technique is suitable for all strains but is difficult to perform and, given the high degree of haemorrhage in the subcutaneous tissue, should be avoided unless there is exceptional scientific justification.

The tarsal vein is easily accessible. The guinea pig is held and the foot restrained. Gentle pressure is applied by massaging above the point (proximally to the animal) at which the blood sample is taken to dilate the vessel. A maximum of three samples can be taken from each hind leg and 0.1 - 0.3 ml of blood can be collected per sample. Samples should be rotated between the hind legs and should be removed first distal to the animal (between the toes) and moved proximally to the animal (towards the ankle). No more than six samples, using both hind legs, should be taken in any 24-hour period. If more blood is needed, other forms of blood sampling should be used, such as surgical cannulation. The number of attempts to take a blood sample should be minimised (no more than two needle sticks in any one attempt). Use of local anaesthetic cream (e.g. EMLA cream) applied to the site 30 minutes prior to sampling can help relieve any pain.

The technique should be performed aseptically, including removal of hair around the sampling site using soap and a scalpel blade. Some haemorrhage in the subcutaneous tissue surrounding the vessel is unavoidable and it can be difficult to stem the blood flow after the blood sample has been taken. Finger pressure on soft tissue for approximately two minutes should be applied to the sampling site and the animal should not be returned to its cage until bleeding stops. Returning the animal to a clean cage can reduce the risk of infection.

Summary

Number of samples No more than six blood samples should be taken in any 24-hour period.
Sample volume 0.1 - 0.3 ml
Equipment 23G needle or lance
Staff resource Two people are required, one to take the blood sample and the other to restrain the guinea pig.
Adverse effects
  • Skin abrasion from the shaving 5%
  • Bruising
  • Infection <1%
  • Haemorrhage 75%
Other Good animal handling is required to restrain the guinea pig for both the shaving and taking the blood sample.

Resources and references

Tarsal vein sampling technique in other animals

This technique is only appropriate for use in the guinea pig.

All blood sampling techniques in the guinea pig

Click here for information on blood vessel cannulation in the guinea pigClick here for information on saphenous vein blood sampling in the guinea pigClick here for information on abdominal/thoracic blood vessel blood sampling in the guinea pigClick here for information on cardiac puncture blood sampling in the guinea pigClick here for information on schedule 1 stunning followed by decapitation for blood sampling in the guinea pigClick here for information on decapitation blood sampling techniques in the guinea pig