Blood sampling: Hamster
Approaches for sampling blood in the hamster, covering non-surgical, surgical and terminal techniques.
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General principles
You should read the general principles of blood sampling page before attempting any blood sampling procedure.
Saphenous vein (non-surgical)
Technique
Sampling from the lateral saphenous vein is a relatively quick method of obtaining blood samples from hamsters. The vein is easily visualised and it does not require the animal to be warmed for sample collection, but shaving away fur is necessary. Hamsters should be habituated to the sound of the electric shaver to minimise additional stress.
Blood is collected from the lateral saphenous vein which runs dorsally and then laterally over the tarsal joint.
Conscious hamsters should be restrained manually for the minimum duration necessary. Hamsters should be habituated to restraint; this will improve the experience of the animal and handler and will lead to obtaining a better-quality blood sample. If sedation is required on welfare grounds care should be taken due to the vasodilation action of some sedatives. Where sedatives contain peripheral vasodilators, doses should be low to avoid prolonged bleeding from the puncture site.
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 shave away hair 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. Aseptic technique should be used.
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 with a swab over the puncture site, or simple relaxation of the operator's grip on the animal's leg. Animals should not be returned to their cage before the blood flow has stopped.
If more than one sample is required legs can be alternated. No more than four blood samples should be taken within any 24-hour period. If more samples are needed, then temporary or surgical cannulation should be considered.
Summary
| Number of samples | No more than four blood samples should be taken within any 24-hour period. |
| Sample volume | Up to 0.15 ml for a single sample, which can usually be repeated at 2-week intervals without disturbances to haematological status. Alternatively, multiple smaller samples (e.g. 0.01 ml daily), taking into account limits on sample volume. |
| Equipment | 27G or 25G needle or lancet to pierce the skin. |
| Staff resource | One person is required to take the blood sample. |
| Adverse effects |
|
Resources and references
- 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. doi: 10.1002/jat.727
- 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.
- Hem A et al. (1998). Saphenous vein puncture for blood sampling of the mouse, rat, hamster, gerbil, guinea pig, ferret and mink. Laboratory animals 32(4): 364-8. doi: 10.1258/002367798780599866
Retro-orbital (non-surgical/terminal)
Technique
Also referred to as peri-orbital, posterior-orbital and orbital plexus bleeding.
Retro-orbital bleeding should typically be performed as a terminal procedure. It should only be used with recovery in rare circumstances with exceptional scientific justification (e.g. where a large blood volume is necessary or where peripheral veins are used for dosing), because of its potential impact on animal welfare.
Where its use is unavoidable, retro-orbital bleeding should only be used under general anaesthesia. Because of the severity of the adverse effects that can occur with this technique, even in skilled hands, it is essential that it is conducted only by staff members competent (practised) in the technique.
Blood is collected from the venous plexus. During the anesthesia, the hamster is restrained, the neck gently scruffed and the eye made to bulge. A capillary tube/pipette is inserted medially, laterally or dorsally. Blood is allowed to flow by capillary action into the capillary tube/pipette. The sample obtained is a mixture of venous blood and tissue fluid, and is not representative of venous blood.
Blood flow can be stopped by applying gentle finger pressure to the soft tissue. A finger should be placed over the closed eyelid for approx. 30 seconds.
Following sampling, the animals should be euthanised via an appropriate schedule one method.
Summary
| Number of samples | It is recommended that only one sample be taken. |
| Sample volume | up to 0.1-0.5 ml |
| Equipment | A glass capillary tube or Pasteur pipette. |
| Staff resource | One person is required to take the blood sample. |
| Other | Procedure should be carried out under terminal anaesthesia. |
| Adverse effects |
|
Resources and references
- Jo EJ et al. (2021). Comparison of murine retroorbital plexus and facial vein blood collection to mitigate animal ethics issues. Laboratory Animal Research 37(12). doi: 10.1186/s42826-021-00090-4
- Heimann M et al. (2009). Blood collection from the sublingual vein in mice and hamsters: a suitable alternative to retrobulbar technique that provides large volumes and minimizes tissue damage. Lab Animal 43(3): 255-60. doi: 10.1258/la.2008.007073
- 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.
- 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. doi: 10.1002/jat.727
Cardiac puncture with recovery (surgical)
Technique
Where cardiac puncture with recovery is used it should always be carried out under general anaesthesia and using aseptic technique. Blood is collected from the left side of the thorax and care should be taken to avoid damaging the lung and heart. A sample of 0.5 ml can be collected. Only one sample should be taken with recovery. A second sample may be taken under terminal anaesthesia.
Blind passage of the needle toward the heart has the potential to cause laceration to large blood vessels or laceration of the heart resulting in pulmonary haemorrhage, haemothorax or cardiac tamponade. Care should be taken to ensure that the needle is inserted only as far as it needs to go into the chest cavity. Pericardial effusion (accumulation of blood within the pericardium) may occur during or after blood sampling and approximately 1 in 500 animals die as a result of the procedure.
Summary
| Number of samples | Only one sample with recovery; a second sample can be taken under terminal anaesthesia |
| Sample volume | 0.5 ml |
| Equipment | An insulin syringe (0.5-2 ml) with an integral needle |
| Staff resource | One person is required to take the blood sample. |
| Adverse effects |
|
Resources and references
- Parasuraman S et al. (2010). Blood sample collection in small laboratory animals. Journal of Pharmacology and Pharmacotherapeutics 1(2): 87-93. doi: 10.4103/0976-500X.72350
- Morton DB et al. (2001). Refining procedures for the administration of substances. Laboratory animals 35(1): 1-41. doi: 10.1258/0023677011911345
Cardiac puncture (terminal)
- Technique
- Summary
- Resources and references
Technique
Cardiac puncture should not be used if the peritoneum needs to be lavaged to harvest cells, as this technique can cause blood to escape into the peritoneal cavity.
Cardiac puncture is a suitable technique to obtain a single, good quality sample from a euthanised hamster or a hamster under deep terminal anaesthesia if coagulation parameters, a separate arterial or venous sample or cardiac histology are not required. It is appropriate for all strains of hamster.
A sample of up to 5 ml of blood can be obtained depending on the size of the hamster and whether the heart is beating. Blood samples are taken from the heart, preferably the ventricle, which can be accessed either via the left side of the chest, through the diaphragm, from the top of the sternum or by performing a thoracotomy. Blood should be withdrawn slowly to prevent the heart collapsing.
Summary
| Number of samples | One |
| Blood volume | Up to 5 ml |
| Equipment | 23G needle |
| Staff resource | One person is required to take the blood sample. |
Resources and references
- Parasuraman S et al. (2010). Blood sample collection in small laboratory animals. Journal of Pharmacology and Pharmacotherapeutics 1(2): 87-93. doi: 0.4103/0976-500X.72350
- Morton DB et al. (2001). Refining procedures for the administration of substances. Laboratory animals 35(1): 1-41. doi: 10.1258/0023677011911345
You should read the general principles of blood sampling page before attempting any blood sampling procedure.
