Which term is the clear straw colored part of the blood after the solids are separated?

• A. Plasma
• B. Blood cells
• C. Platelets
• D. Serum

Answer: (D)

When blood is allowed to clot and the solid clot is removed, the liquid that remains is serum. Serum is clear and straw-colored because the solids (clot) are gone, and clotting factors like fibrinogen have been used up in forming the clot. If blood is collected with an anticoagulant so it doesn’t clot and is then centrifuged, the liquid obtained is plasma, which still contains fibrinogen and other clotting factors. So the liquid after the solids are separated (post-clot) is serum.