What tube would produce a serum sample?

The red top tube is designed specifically to obtain a serum sample. This tube contains no additives, allowing the blood to clot and facilitating the separation of serum from the clot when centrifuged. Serum is the liquid portion of the blood that remains after clotting has occurred, making the red top tube ideal for various tests requiring serum analysis.

In contrast, the other tubes mentioned contain additives that either prevent clotting or alter the properties of the blood for different types of tests. For example, the green top tube typically has heparin as an additive and is used for tests that require plasma rather than serum. The light blue top tube contains sodium citrate, which is another anticoagulant; therefore, it is primarily used for coagulation studies that necessitate plasma. The purple top tube, often containing EDTA, is utilized for hematology tests requiring whole blood, so it cannot produce serum either.

Understanding the specific purpose and function of each tube type is crucial in phlebotomy, as it ensures the proper collection and processing of blood samples for accurate laboratory results.