After an EDTA tube is centrifuged, what is the thin layer between the plasma and the packed red cells?

Explanation

The buffy coat is the pale layer of leukocytes and platelets that settles between the denser red cells and the lighter plasma. A fibrin clot forms only in a tube without anticoagulant, and separator gel exists only in gel tubes, not in a standard lavender tube. Hemolyzed plasma appears as pink or red discoloration throughout the plasma rather than as a discrete layer.