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Difference Between Serum and Plasma


A living body constitutes numerous cells, tissues, muscles, blood, plasma, and much more inside it. Similar are the two terms, serum and plasma, acquiring a significant portion of a body. Scientists have vigorously used them to perform different blood tests in laboratories, being abundant in blood. It is the central part of an organism that also helps collect information about various illnesses.

Serum and plasma compose proteins, vitamins, hormones, toxins, electrolytes, and whatever tiny substance is present around it. We can also quickly disintegrate them using the centrifugation method and utilize them for therapeutic and diagnostic purposes. The difference between them lies in such protein-like substances. A liquid material that detaches from the blood when it coagulates is called serum. At the same time, plasma is another liquid substance that firmly grasps blood cells in suspension. Let’s glance at the tabular comparison between the two for better awareness.

Serum and Plasma Difference – Comparison Chart

Basis of DifferentiationSerumPlasma
Density1.024 g/ml1.025 g/ml
AntibodiesCross reacts with
recipient antigen
Fight against
foreign body  
Life SpanSeveral days at
Stored yearly
Water ContentConsists of almost
90% water
Consists of around
92-95% water
AnticoagulantNot neededEDTA and Heparin
UsageBlood typing
diagnosing test
Diagnosing blood
clotting like disorders

What is Serum in Blood?

If we generally speak about the serum, it’s everything in the plasma, excluding blood cells and clotting factors. Being a liquid material, Serum is an essential source of different blood substances, such as different types of antigens, types of antibodies, proteins, hormones, and electrolytes. This portion of blood helps diagnose multiple diseases, for instance, hypertension, diabetes, cholesterol concentration, etc.

What is Plasma in Blood?

The entire blood contains almost 55% of plasma, further accumulating the maximum (90%) water. Other than water, albumin and fibrinogen help prevent fluid from leaking into adjacent cells and forming blood clots, respectively. The crucial role of blood plasma is to distribute all essential nutrients, antibodies produced by lymphocytes, proteins, hormones, and other substances in the body. Since it helps different cells get their desired substances, they deposit their waste while moving around. Hence, plasma is also responsible for waste removal.

Difference between Serum and Plasma


As we have mentioned that both are distinct from each other, so there are questions arising, like “What is the difference between serum and plasma?” Let’s find out the differences in detail below.



A liquid portion of blood that exists after the coagulation completes, excluding clotting factors and blood cells, is called serum.


It is a yellow-colored fluid present in the blood which constitutes more than half of the blood volume to perform numerous functions.

Role of Centrifugation


We can usually obtain Serum through centrifugation after clotting, which is a comparatively tricky process.


On the other hand, plasma is acquired through the same process but before clotting.


Major Constituents


A serum holds all essential substances in the blood, for example, antibodies, proteins, hormones, electrolytes, etc.


This blood substance contains maximum water content, proteins (like globular and fibrous), and also the clotting factors. Not to forget, it excludes all blood clotting factors.

Volume & Density


It has a comparatively lesser volume than plasma, with a density of 1.024 g/ml.


Whereas plasma has about 55% of the whole blood with a density of 1.025 g/ml.

Primary Function


Nowadays, experts are using an animal serum to produce anti-venoms, antitoxins, and such anti-substances for vaccinations. It is typically involved to diagnose diabetes, high cholesterol level, uric acid level, and blood pressure through blood tests.


On the other hand, plasma helps a body transport excretory metabolites and similar substances inside a body. Another primary function of plasma is to regulate a body’s temperature and also to maintain blood pressure.

Final Verdict

Despite being the components of blood, serum and plasma are entirely different. They might be similar in having protein molecules but varies at the differential isolation process. The serum is the excess fluid after blood coagulation, whereas plasma is the entire liquid portion where blood cells are transported.

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