Haji Siyamuddin Ansari: The Key Difference Between Plasma and Serum
Haji Siyamuddin Ansari, Medical Practitioner, shared a post on X:
”Plasma vs Serum Clear Clinical Difference
Core Difference
Feature: Plasma | Serum
Definition: Liquid part of blood with anticoagulant | Liquid after clotting
Clotting factors: Present including fibrinogen | Absent because fibrinogen is consumed
How obtained: Blood with anticoagulant then centrifuged | Blood allowed to clot then centrifuged
Appearance: Slightly cloudy yellow | Clear straw colored
Key use: Coagulation tests such as PT and aPTT | Biochemistry and serology
High-Yield Concept
Plasma equals serum plus clotting factors
Serum equals plasma minus fibrinogen
Clinical Relevance
Use plasma when studying coagulation pathways
Use serum for:
LFT and RFT
Hormones
Antibodies
One-line answer for your post
‘Plasma contains clotting factors including fibrinogen, while serum is plasma without clotting factors after coagulation.’ ”

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