What is the maximum volume of blood that can safely be taken from a hamster?

• A. 0.65 mL
• B. 6.5 mL
• C. 0.065 mL
• D. 1.3 mL

Answer: (A)

Small animals like hamsters have very limited circulating blood, so any phlebotomy must remove only a tiny fraction of that volume. A typical hamster around 100 g has about 6–7 mL of blood. Keeping a single draw to roughly 10% of total blood volume minimizes the risk of hypovolemia and instability, which is about 0.6–0.7 mL. The commonly accepted safe maximum is around 0.65 mL, balancing the need for enough sample with the animal’s safety. Larger volumes would compromise circulation and could cause serious harm, while much smaller volumes might be impractical for tests.