Difference Between Agglutination and Precipitation (With Table)

The interconnection between an antibody and its equivalent antigens used to find several pathogens and microbes. This interaction results in the following reactions: Agglutination reactions and precipitation reactions.

The difference between Agglutination and precipitation is Agglutination reaction happens when one antibody binds several antigens resulting in the clumping of cells. On the converse, precipitation reaction is the interaction of soluble antigens with soluble antibodies resulting in an insoluble compound called a precipitate. But every agglutination and precipitation reaction results in the formation of dense species in a given solution. Again, this newly formed dense mass will remain in solution as pendant particles or drain to the bottom of a given vessel.

Agglutination VS Precipitation

The main difference between Agglutination reaction and Precipitation reaction is that in agglutination reaction soluble antigen reacts with proteins produced by the immune system results in forming “agglutinin” In precipitation, however, soluble antigens react with proteins produced by the immune system, thereby forming a precipitate.

Agglutination reaction is the process In which dense mass particles are formed. The antigen is in a precipitated form and the size of the antigen is always larger.The reaction is considered to be more sensitive and the final product appears as insoluble aggregates.

A precipitation reaction is the process of the formation of insoluble compact mass from the reaction of ions present in the solution. In precipitation reaction, the antigen is in an insoluble form and smaller in size.The final product of the agglutination reaction shown is a large visible aggregate.

Comparison Table Between Agglutination and Precipitation

DefinitionAgglutination reaction is the process of forming dense mass from particles present in solution. A precipitation reaction is the process of the formation of insoluble compact mass from the reaction of ions present in the solution.
Solubility Of The Resulting CompoundIn Agglutination reaction, the antigens formed Are sublimated.In precipitation reaction, the antigen is an insoluble form.
SizeThe antigenic form is larger. The size of the Antigen form is comparatively smaller.
SensitivityAgglutination is more sensitive.Precipitation reactions are less sensitive.
Resulted Compounds Formed The resulting compounds of agglutination reactions are called agglutinate. The compounds formed by the precipitation reaction are called precipitates.
Appearance Of The Final Product The end product of agglutination reaction we can see aggregates. The final product obtained from the precipitation reaction is a large amount of insoluble visible precipitate.

What is Agglutination?

Agglutination is a process in which particles accumulate to form a single large dense mass. This newly formed solid mass can either sink or may float. The end product is called “Agglutinate”.

Agglutination occurs with the particles that are already present in the solution. The antigen forms are in segmented form and are comparatively smaller. Agglutination reactions are more sensitive and the compound formed is called agglutinins, which we can see as aggregates.

In the medical procedure, Agglutination reactions can be used for blood grouping, transfusion, for identification of microbial culture. Agglutination is used to check if a patient has any bacterial infection.

Blood grouping is a good example of agglutination. Blood grouping is very crucial during the blood transfusion process, if an unmatched blood group is provided it can lead to the formation of clumps in red blood cells since antibodies will react with the blood cells forming lumps in the blood.

What is Precipitation?

Precipitation is the process of formation of an insoluble solid mass in a liquid solution from the reaction of ions present in the solution. The Resulting compound formed due to precipitation is called “precipitate.”

The precipitation reaction is less sensitive and the antigenic formed is a large mass of insoluble material with visible precipitate. Several precipitation methods are used in clinical labs for the identification of diseases, quantitative analysis, and pigment formation.

Example of a precipitation reaction:

-Immunodiffusion precipitation test.

It is a process used to detect the presence of an antigen in the form of any foreign substance, which can harm the immune system of the body such as immunoglobulins and other nuclear antigens.

In this process, antigen and antibodies are placed together as one in two alongside Wells, as they both diffuse towards each other, and precipitate is formed in the form of lines as the result of the interaction of antigen and antibodies.

Based on the formation of a precipitate, different viruses, and traces of antigens can be found.

Main Differences Between Agglutination and Precipitation

  1. Agglutination is forming a solid mass from particles present in the solution, whereas precipitation is forming of insoluble solid mass from the reaction of ions that are already present in the solution.
  2. The antigen formed in agglutination reactions is smaller as the antigens formed during the precipitation reactions are comparatively larger.
  3. Agglutination is based on the principle of clumping of particles whereas precipitation is based on the formation of insoluble molecules formed by the interaction of antigen and antibodies.
  4. The starting molecules required for agglutination are particles whereas the starting molecules required for precipitation are ions.
  5. In agglutination, insoluble antigens are involved whereas in precipitation soluble antigens are involved.


Both agglutination and precipitation methods are used for many human as well as clinical and biologic assays. Agglutination is used in organic terms, where precipitation is used in chemical clinical analysis.

In both agglutination and precipitation, the outcome is seen the same but still, the process is distinguishable. Agglutination can be used during the blood transfusion process blood grouping precipitation can be useful for conditional analysis and in the genesis of pigments.

The difference between agglutination and precipitation is In Agglutination solid mass is formed due to particles present in it, which are called agglutinates whereas in precipitation soluble solid mass is observed due to reactions of ions that are already present in the solution, which is called the precipitate.


  1. https://www.tandfonline.com/doi/pdf/10.1080/01971520009349532
  2. https://www.sciencedirect.com/science/article/pii/0022519374901301