Which statement about serum and plasma is correct?

Which statement about serum and plasma is correct?

• A. Only A is correct
• B. Only B is correct
• C. Neither statement is correct
• D. Both statements are correct

Answer: (D)

Understanding serum versus plasma hinges on how the blood is processed and what remains in the liquid after separation. Serum is the liquid that stays after blood has clotted and is removed by centrifugation; in that process, fibrinogen and other clotting factors become part of the clot, so they are not present in serum. Plasma, on the other hand, is obtained from blood collected with an anticoagulant and then centrifuged; it keeps the clotting factors, including fibrinogen, in the liquid portion. If the two statements in question refer to serum lacking clotting factors and plasma containing clotting factors, both are true. That’s why the best conclusion is that both statements are correct. In practice, this distinction explains why serum is often used for many chemistry tests, while plasma is preferred when assessing clotting functions or factors.

Understanding serum versus plasma hinges on how the blood is processed and what remains in the liquid after separation. Serum is the liquid that stays after blood has clotted and is removed by centrifugation; in that process, fibrinogen and other clotting factors become part of the clot, so they are not present in serum. Plasma, on the other hand, is obtained from blood collected with an anticoagulant and then centrifuged; it keeps the clotting factors, including fibrinogen, in the liquid portion.

If the two statements in question refer to serum lacking clotting factors and plasma containing clotting factors, both are true. That’s why the best conclusion is that both statements are correct. In practice, this distinction explains why serum is often used for many chemistry tests, while plasma is preferred when assessing clotting functions or factors.