- Resources and references
- Saphenous vein sampling in other animals
- All blood sampling techniques in the rat
Please read the general principles of blood sampling page before attempting any blood sampling procedure.
Sampling from the lateral saphenous vein is a relatively quick method of obtaining blood samples from all strains of rat. It does not require the rats to be warmed.
Slides and videos of restraint, shaving and sampling for this technique with mice are available on the websites of the Norwegian Reference Centre for Laboratory Animal Science and Alternatives.
Blood is collected from the lateral saphenous vein which runs dorsally and then laterally over the tarsal joint. To improve visualisation of the vein the sample site can be shaved with electric clippers. Shaving need only be repeated as the hair grows again.
The rat should be restrained either manually or using a restraint tube. This can cause stress and therefore the duration of restraint should be minimised. Where a restraint tube is used, it should be appropriate to the size of the rat. All forms of restraining equipment should be frequently washed to prevent pheromonally-induced stress or cross-infection.
To collect blood, the hind leg should be immobilised in the extended position by applying gentle downward pressure immediately above the knee joint. This stretches the skin over the ankle, making it easier to clip and immobilise the saphenous vein. Please note that hair removal by shaving with a scalpel blade is no longer recommended as it removes the epidermal layers of the skin. An aseptic technique should be used. Anaesthesia is not necessary but may be used on welfare grounds for animals that are difficult to hold. Where sedatives contain peripheral vasodilators, doses should be low to avoid prolonged bleeding from the puncture site. The number of attempts to take a blood sample should be minimised (no more than three needle sticks in any one attempt). Blood is collected by capillary action into a haematocrit tube or passively into a tube.
Blood flow can be stopped by gentle finger pressure over the puncture site, or simple relaxation of operator's grip on the animal's leg. Animals should not be returned to their cage before the blood flow has stopped.
No more than four blood samples should be taken in any 24-hour period. If more samples are needed, then surgical cannulation or temporary cannulation should be considered. For multiple samples, the scab or the blood clot should be removed.
Rats can show temporary favouring of the limb following sampling from the saphenous vein.
|Number of samples||No more than four blood samples should be taken within any 24-hour period|
|Sample volume||Up to 0.2 ml may be taken for a single sample, which can usually be repeated at 2-week intervals without disturbances to haematological status. Alternatively, multiple smaller samples (e.g. 0.02 ml daily) may be drawn, taking into account limits on sample volume.|
|Equipment||23G needle or lance|
|Staff resource||One person if a restraint tube is used. Where manual restraint is used, two people are required: one for handling the rat and one for taking the blood sample.|
- Hem A, Smith AJ, Solberg P (1998), Blood collection using the saphenous vein: An alternative to retro-orbital collection, Vivarium and the University of Bergen
- Diehl KH, et al (2001). A good practice guide to the administration of substances and removal of blood, including routes and volumes. Journal of applied Toxicology 21.1: 15-23
- van Herck H, et al (2001). Blood sampling from the retro-orbital plexus, the saphenous vein and the tail vein in rats: comparative effects on selected behavioural and blood variables. Laboratory Animals 35(2): 131-139
- Luzzi M, et al (2005). Collecting blood from rodents: a discussion by the Laboratory Animal Refinement and Enrichment Forum. Animal Technology and Welfare 4 (2) 99-102
- Abatan OI, Welch KB, & Nemzek JA (2008). Evaluation of saphenous venipuncture and modified tail-clip blood collection in mice. Journal of the American Association for Laboratory Animal Science, 47(3): 8-15
- Hem A, Smith AJ, & Solberg P (1998). Saphenous vein puncture for blood sampling of the mouse, rat, hamster, gerbil, guinea pig, ferret and mink. Laboratory animals 32(4): 364-368