Which color top is used for a serum sample with no additive?

Which color top is used for a serum sample with no additive?

• A. Red
• B. Gold
• C. Gray
• D. Light Blue

Answer: (A)

Red-topped tubes contain no additive. They’re used when a serum sample is needed without any substances that could alter the test results; you collect the blood, allow it to clot, then centrifuge to obtain serum free of additives. The other colors include additives that change how the sample behaves or what’s measured: gold tops have a clot activator and gel for serum separation, gray tops include a glycolytic inhibitor/anticoagulant, and light blue tops contain anticoagulant sodium citrate for plasma studies. For a serum sample with no additive, the red top is the best choice.

Red-topped tubes contain no additive. They’re used when a serum sample is needed without any substances that could alter the test results; you collect the blood, allow it to clot, then centrifuge to obtain serum free of additives. The other colors include additives that change how the sample behaves or what’s measured: gold tops have a clot activator and gel for serum separation, gray tops include a glycolytic inhibitor/anticoagulant, and light blue tops contain anticoagulant sodium citrate for plasma studies. For a serum sample with no additive, the red top is the best choice.