What is the function of the red top tube in laboratory testing?

The red top tube is primarily used for serum testing, which includes a variety of chemistry tests and specific assays such as prostate-specific antigen (PSA) testing. The function of the red top tube is to allow blood to clot, separating the serum from the cellular components once centrifuged. This makes it particularly suitable for tests that require serum, as it eliminates the need for anticoagulants that could interfere with certain tests.

Tests like prostate-specific antigen assess levels in the blood that can help screen for prostate conditions. Additionally, other chemistry panels performed on serum, such as liver function tests or electrolyte panels, can also be carried out using a red top tube. The versatility of the red top tube for various serum testing makes it an essential tool in the laboratory setting.

In contrast, blood cultures require specific media to detect microbial growth, while complete blood counts (CBC) and coagulation studies are typically performed using other tube types (such as lavender or blue top tubes) that contain additives needed for those particular tests.