Difference Between Serology and Immunology

Key Difference – Serology vs Immunology

Serology and Immunology are both important disciplines within the field of medicine, but there exist distinct differences between the two that make each of the subjects sufficiently independent on each other. Both serology and immunology are related and connected to each other and contribute to a better understanding of disease and infection in the body. The connections between both these disciplines lie at the point where reactions found in immunology form the basis of serology or serological techniques. In other words, serology can also be considered a branch of immunology with it focusing on the diagnostic values of the immune system. Despite this connection, there are clear differences between serology and immunology. The key difference between serology and immunology is that the Serology is the study of serum while immunology is the study of the immune system. However, before taking a look at these differences, let us first understand ‘serology’ and ‘immunology’.

What is Serology?

Serology is the study of serum. Serum is a part of blood. It is usually formed by allowing blood to clot, the process of clotting removes the clotting factors and whole cells from the blood leaving behind a yellow coloured liquid. This liquid is referred to as serum, and it contains antibodies, antigens, microorganisms if any, hormones, electrolytes, and other proteins. Serology, in a wider context basically, deals with the quantitative and qualitative analysis of these various components. However, serology is known for the qualitative detection or quantitative analysis of antibodies or antigens concerning infection or disease diagnosis.

There exist a wide variety of serological techniques used in the field of medical laboratory sciences that aid in this matter. Some of these are enzyme linked immunosorbent assay (ELISA), immunofluorescence assay (IFA), agglutination tests (AT), complement-fixation tests (CFT), hemagglutination assay (HA) and hemagglutination inhibition tests (HAI) etc. Almost all of these techniques are based on reactions achieved in the context of specificity between components of the immune system, i.e. antibodies, and antigens. Serology is also used in the field of forensics aiding in crime solving. It is also used in epidemiology, to determine the serological outcome of a vaccine administered to the population or simply to determine the abundance of a specific antibody (particularly one produced in response to disease or infection) in a population. This is also called seroepidemiology.

serology vs. immunology key difference

The Widal test: Serological test

What is Immunology?

Immunology is the study of the body’s immune system. The scope of this discipline is extremely wide and basically involves the physiological study of the immune system i.e. the study of the tissues, organs and cells related to the immune system. It also involves the study of the immune system’s response to a foreign body or antigen which includes the production of antibodies. It also involves the study of the immune system in response to allergens, the study of autoimmune diseases, the study of the system in response to cancer cells, the study of Immunotherapy and the study of diseases or infections of the immune system.

difference between serology and immunology

MRSA (yellow) being ingested by neutrophil (purple)

What is the Difference Between Serology and Immunology?

Definition of Serology and Immunology

Serology: Serology is the study of serum.

Immunology: Immunology is the study of the body’s immune system.

Characteristics of  Serology and Immunology

Nature of Study

Serology: Serology majorly refers to the in vitro study of blood serum rather than the study of it is in vivo nature.

Immunology: Immunology is the study the immune system majorly in a state of in vivo.


Serology: Serology is a comparatively smaller discipline compared to immunology.

Immunology: Immunology has a relatively wider scope than serology.

Links to other Disciplines

Serology: Serological techniques are used as tools in various other disciplines of medicine like forensics, medical laboratory diagnostics, and epidemiology.

Immunology: On the other hand, immunology is itself a major discipline in the field of medicine.

Use in Diagnosis

Serology: Serology in popularity is known for its use in the diagnosis of diseases or infection, achieved by detecting either specific antibodies or antigens in the serum of question.

Immunology: Antibodies themselves are byproducts of the immune system produced in response to the presence of an antigen in the body.


Image Couresy:
“MRSA, Ingestion by Neutrophil” by National Institutes of Health (NIH) – National Institutes of Health (NIH). (Public Domain) via Wikimedia Commons 
“Widal Test Slide” by Sujith – Own work.  (CC BY-SA 3.0) via Wikimedia Commons