CPT (Certified Phlebotomy Technician) Practice Exam

Blood specimen tubes should be mixed after collection by inverting them gently 5 to 8 times. This method ensures that the anticoagulants or additives within the tube properly mix with the blood without causing hemolysis or damaging the blood cells. Inversion distributes the additive evenly throughout the specimen and preserves the integrity of the sample for testing.

Gently inverting the tubes helps to maintain the quality of the specimen, as shaking vigorously or rolling in the hands may cause turbulence that can lead to hemolysis. Additionally, keeping the tubes upright for an extended period does not facilitate proper mixing and can result in a separation of components, which is not ideal for many types of analyses. Therefore, the recommended practice for mixing blood tubes effectively balances thorough mixing while minimizing the risk of sample damage.