Serum does not contain which substance?

Serum does not contain which substance?

• A. Albumin
• B. Glucose
• C. Fibrinogen
• D. Urea

Answer: (C)

Serum is the liquid part of blood that remains after it has clotted and been centrifuged. During clotting, fibrinogen is converted into fibrin to form the clot, so the fibrinogen protein is used up and ends up in the clot itself. That’s why it is not detectable in serum. Albumin, glucose, and urea, on the other hand, are dissolved in the serum and remain in the liquid portion after clotting, which is why you can measure them in serum samples. If you need to assess fibrinogen specifically, you’d use plasma obtained with an anticoagulant, since plasma still contains fibrinogen.

Serum is the liquid part of blood that remains after it has clotted and been centrifuged. During clotting, fibrinogen is converted into fibrin to form the clot, so the fibrinogen protein is used up and ends up in the clot itself. That’s why it is not detectable in serum.

Albumin, glucose, and urea, on the other hand, are dissolved in the serum and remain in the liquid portion after clotting, which is why you can measure them in serum samples. If you need to assess fibrinogen specifically, you’d use plasma obtained with an anticoagulant, since plasma still contains fibrinogen.