Blood Collection

Volume

The maximum amount of blood removed from an animal is based on total blood volume (TBV) and the need to avoid physiologic changes in response to blood loss. Estimates of TBV vary greatly and range from <40 to >90 ml/kg body weight depending on species. The NC3R's website provides a table showing practical blood sample volumes for laboratory animals, domestic species and non-human primates. In general, removal of <10% of TBV not more than every 2-3 weeks will avoid adverse effects and allow adequate physiologic recovery time. However, TBV can be significantly lower than mean estimates in animals that are older, obese or otherwise physiologically abnormal.

For rodents: A safe guideline for total maximum volume of blood to remove from a healthy animal is 1% of body weight (BWT) either as a single collection or as multiple collections over a 2 week period.

For example, using the 1% of BWT guideline, a mouse that weighs 25 gm could have either 0.25 ml of blood withdrawn at a single sampling or a total of 0.25 ml of blood withdrawn in multiple samplings over a 2 week period. Note that if the total volume is withdrawn as a single collection it is recommended that replacement fluid therapy be provided to the animal (not >1.0 ml SQ or IP injection of sterile isotonic fluid such as lactated ringers or 0.9% NaCl). More detailed information on methods of blood collection in laboratory animals is available at NC3Rs.

ARP personnel are available to provide training and discuss the advantages and disadvantages for each blood collection technique for your experiment.