STEP 01Animal Blood CollectionAs required by institutional and ethical guidelines, the animal is anesthetized before blood collection. Blood collection can be accomplished depending on the size of the animal. For small animals such as rats and mice, blood is typically collected from the tail vein, retro-orbital sinus, or by cardiac puncture. For larger animals such as non-human primates, blood is commonly collected from a vein, mainly the saphenous or femoral vein. To prevent clotting, an anticoagulant is added immediately to the blood. Heparin or EDTA is usually used as anticoagulant. The blood is then gently mixed by inverting the tube several times. Vigorous shaking is avoided to prevent hemolysis.