A vacutainer that contains no anticoagulant has a stopper colored ____.

A vacutainer that contains no anticoagulant has a stopper colored ____.

• A. Blue
• B. Green
• C. Purple
• D. Red

Answer: (D)

Stopper color signals what’s inside the tube—whether it contains anticoagulants or not. A tube with no anticoagulant is used when you want serum, because the blood will clot and you can separate serum after centrifugation. The red stopper is associated with no additive, so it’s the choice for serum collection. Other colors indicate specific anticoagulants (blue for citrate, green for heparin, purple for EDTA, gray for fluoride/oxalate), which prevent clotting and yield plasma or whole blood for different tests. So red is the best answer because it denotes no anticoagulant present, allowing clotting to occur and serum to be obtained.

Stopper color signals what’s inside the tube—whether it contains anticoagulants or not. A tube with no anticoagulant is used when you want serum, because the blood will clot and you can separate serum after centrifugation. The red stopper is associated with no additive, so it’s the choice for serum collection. Other colors indicate specific anticoagulants (blue for citrate, green for heparin, purple for EDTA, gray for fluoride/oxalate), which prevent clotting and yield plasma or whole blood for different tests. So red is the best answer because it denotes no anticoagulant present, allowing clotting to occur and serum to be obtained.