Which of these tubes must never be placed on a blood rocker after being filled with blood?

Which of these tubes must never be placed on a blood rocker after being filled with blood?

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

Answer: (D)

The important idea here is that serum tubes should be allowed to clot without agitation. A red top tube has no anticoagulant, so after blood is drawn it must form a clot undisturbed. Rocking or shaking it can disrupt the clotting process or create microclots, which compromises the quality of the serum after centrifugation. Other tubes contain anticoagulants (such as citrate, heparin, or EDTA) and are intended to be mixed by gentle inversion to distribute the additive evenly. They are not placed on a rocker for mixing; the key point is that the serum tube is the one that must not be rocked because you want proper, undisturbed clot formation before centrifugation.

The important idea here is that serum tubes should be allowed to clot without agitation. A red top tube has no anticoagulant, so after blood is drawn it must form a clot undisturbed. Rocking or shaking it can disrupt the clotting process or create microclots, which compromises the quality of the serum after centrifugation.

Other tubes contain anticoagulants (such as citrate, heparin, or EDTA) and are intended to be mixed by gentle inversion to distribute the additive evenly. They are not placed on a rocker for mixing; the key point is that the serum tube is the one that must not be rocked because you want proper, undisturbed clot formation before centrifugation.