Question

A drop of each of the following, is placed separately on four slides. Which one of them will not coagulate?

• A. Blood serum
• B. Sample from thoracic duct of lymphatic system
• C. Whole blood from pulmonary vein
• D. Blood plasma

Answer 1

Answer: (A)

Blood serum

Blood serum is the component of blood that has neither a blood cell nor a clotting factor. Serum includes all proteins not used in blood clotting (coagulation) and all the electrolytes, antibodies, antigens, hormones, and any exogenous substances (e.g., drugs and microorganisms). Hence, serum does not clot. Thus, the correct answer is option A.