The liquid portion of the blood that remains after clotting is called

• A. Plasma
• B. Serum
• C. Lymph
• D. Serous fluid

Answer: (C)

When blood clots, the liquid left behind is serum. This happens because clotting factors, especially fibrinogen, are consumed to form the clot, so they’re removed from the liquid portion. What remains is plasma without those clotting components, i.e., serum. Plasma is the liquid component when blood is collected with anticoagulants and still contains fibrinogen and other clotting factors. Lymph is not blood; it’s extracellular fluid that circulates through the lymphatic system. Serous fluid is produced by serous membranes and lines body cavities, not the blood clotting process. So the liquid portion after clotting is serum.