Question

which of the following substances cannot prevent coagulation when directly added to a blood sample (i.e., in a test tube)?

Answer 1

Red blood cells (RBCs) cannot prevent coagulation when directly added to a blood sample. In fact, RBCs are involved in the process of coagulation as they release substances that promote clotting.

Other substances such as heparin and citrate can prevent coagulation when added to a blood sample.