Skip to main content

Welcome to the new NC3Rs site, find out more about the changes and improvements we have made.

NC3Rs: National Centre for the Replacement Refinement & Reduction of Animals in Research
Guidance

Blood sampling: Hamster

Approaches for sampling blood in the hamster, covering non-surgical, surgical and terminal techniques.

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. It does not require the animal to be warmed for sample collection.

Slides and videos of restraint and sampling for this technique are available on the websites of the Norwegian Reference Centre for Laboratory Animal Science and Alternatives and the University of Bergen.

Blood is collected from the lateral saphenous vein which runs dorsally and then laterally over the tarsal joint.   

Conscious hamsters 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 for the size of the hamster. 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 the 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 within any 24-hour period. If more samples are needed, then temporary or surgical cannulation should be considered. The scab or blood clot is removed for multiple samples.

Hamsters may show temporary favouring of the opposite limb following sampling from the saphenous vein.

Summary

Consideration Recommendation

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 lance

Staff resource

One person is required to take the blood sample.

Adverse effects

  • Bruising
  • Haemorrhage
  • Infection
  • Temporary favouring of the opposite limb

Resources and references

  1. 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
  2. Luzzi M et al. (2005). Collecting blood from rodents: a discussion by the laboratory animal refinement and enrichment forumAnimal Technology and Welfare 4(2): 99-102.
  3. 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. 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

Consideration Recommendation
Number of samples

It is recommended that only one sample be taken.

Sample volume

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

  • Retro-orbital haemorrhage resulting in haematoma and excessive pressure on the eye
  • Corneal ulceration, keratitis, pannus formation, rupture of the globe and micro-ophthalmia caused by proptosis of the globe
  • Damage to the optic nerve and other intra-orbital structures which can lead to deficits in vision and blindness
  • Fracture of the fragile bones of the orbit and neural damage by the micro-pipette
  • Penetration of the eye globe itself with a loss of vitreous humour

Resources and references

  1. 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 
  2. 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
  3. Luzzi M et al. (2005). Collecting blood from rodents: a discussion by the laboratory animal refinement and enrichment forumAnimal Technology and Welfare 4(2): 99-102.
  4. 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

Collection of blood from the heart is the most accessible route in the hamster. However, given the invasive nature of the procedure and that it requires general anaesthesia, sampling from the saphenous vein should always be considered first.

Where cardiac puncture with recovery is used it should always be carried out under general anaesthesia and using an 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

Consideration Recommendations
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
  • Laceration to large blood vessels or laceration of the heart resulting in pulmonary haemorrhage, haemothorax or cardiac tamponade
  • Pericardial effusion (accumulation of blood within the pericardium) may occur during or after blood sampling

Resources and references

  1. 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
  2. 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

Consideration Recommendation
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

  1. 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
  2. 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.

Five needles with empty syringes on a pale blue background

Blood sampling resources