Which blood collection tube is used to yield a serum sample?

The choice of using a red or tiger top blood collection tube for obtaining a serum sample is based on the composition and function of these tubes. The red top tube contains no additives, allowing the blood to clot naturally. This coagulation process facilitates the separation of the liquid serum from the cellular components of the blood once it has been spun in a centrifuge.

The tiger top tube, which is often referred to as a serum separator tube, is designed with a gel that forms a barrier between the serum and the cellular components after centrifugation. This feature simplifies the removal of serum, making it particularly useful for serum assays.

In contrast, tubes with blue tops contain sodium citrate, which is used primarily for coagulation studies, preventing clotting. Green top tubes are heparinized and are intended for plasma collection rather than serum. Purple top tubes contain EDTA and are also used for plasma, specifically for blood counts and cell morphology.

Therefore, the use of a red or tiger top tube for serum samples is the appropriate choice due to their specific design that allows for effective serum collection and separation.