This document is intended to provide guidance regarding safe volumes and common routes for blood collection from laboratory animals.
The volume of blood collected in most mammals is generally not a problem. However, repeated blood sampling in mice, rats, hamsters, guinea pigs, small cats, birds and some fish can be problematic because of their small body size. In order to prevent anemia, electrolyte imbalance, hypovolemic shock or other complications, the following guidelines should be followed:
As a general rule, 1% of an animal’s body weight (measured in grams) can be collected in blood (measured in milliliters) within a 24-hour period, every 14 days. For example, 0.3 ml can be collected once every two weeks from a 30-gram mouse. Alternatively, 0.05 ml of blood can be collected hourly for 6 consecutive hours from a 30-gram mouse, every two weeks (0.05 × 6 = 0.3 ml). Although blood volume is rapidly restored in an animal after blood collection, a two-week “rest period” is needed for blood constituents (red blood cells, platelets, clotting factors, etc.) to be regenerated by the body.
If blood needs to be collected once a week, it is recommended that not more than 0.5% of the animal’s body weight be removed within a 24-hour period. For example, 0.15 ml can be collected once a week from a 30-gram mouse. This volume can be further divided if blood needs to be collected more frequently. For example, 0.03 ml can be collected once a day for five days from a 30-gram mouse, provided the mouse is given a one week (or greater) “rest period” before blood is collected again. The key to determining how much and how frequently blood can be drawn depends on the “rest period” between blood collections.
Blood collection can be performed from several sites on mice, rats and hamsters. Below is a table containing the summary of sites and collection frequencies from these sites. Typical venipuncture sites for non-rodent species may include but are not limited to jugular, cephalic, lateral saphenous, and aural (rabbit) sites. Blood collection frequency must take into account maximum blood volumes collected with intended rest period (see above).
|Retro-orbital sinus||Yes, general anesthesia||Same eye, once every 2 weeks; can be performed on same eye if blood is collected within 30 minutes of the first sample||Good for large blood collection on a weekly (or monthly) basis|
|Saphenous vein||No||Multiple||Good for multiple collection of small volumes|
|Tail vein||No||Multiple||Good for multiple collection of small volumes|
|Tail nick||No||Multiple||Good for multiple collection of small volumes|
|Submandibular nick||No||Multiple||Good for multiple small or single large blood collection volumes|
|Cardiac puncture||Yes; general anesthesia, terminal procedure only||Not Applicable||Good for large, one-time collection|
For assistance with blood collection sites in other species, or for further assistance in tailoring blood volumes and blood collection frequencies to your project needs or for animals of compromised health status, please contact the Campus Veterinary Services at 530-752-0514 or.
1. Diehl, K,. et al., A Good Practice Guide to the Administration of Substances and Removal of Blood, Including Routes and Volumes, J Appl Toxicol 21:15-23, 2001
Date: May 31, 2012
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Supersedes: Aug 24, 2006