Question

Which of the following is NOT present in serum?

• A. Albumin \(\alpha\)1
• B. Albumin \(\beta\) fraction
• C. Fibrinogen
• D. Globulin

Hint:

Plasma vs Serum:
Plasma = Water + Albumin + Globulins + FIBRINOGEN (Clotting factors intact).
Serum = Plasma MINUS Fibrinogen (No clotting factors).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Blood fractionation differentiates whole plasma (liquid fraction of uncoagulated blood) from serum (liquid remaining after whole blood clot retraction).
Key Formula or Approach:
\[ \text{Serum} = \text{Plasma} - \text{Fibrinogen and Clotting Factors (II, V, VIII)} \]

Step 2: Detailed Explanation:
In hematology and clinical biochemistry:
- When whole blood clots, the soluble plasma glycoprotein Fibrinogen (Factor I) is proteolytically cleaved by thrombin into insoluble fibrin monomers that polymerize and cross-link to form the blood clot meshwork.
- The expressed straw-colored supernatant fluid is Serum, which contains albumins, globulins, electrolytes, and antibodies, but is completely devoid of fibrinogen.

Step 3: Final Answer:
Hence, Fibrinogen is NOT present in serum, corresponding to option (C).