Differences Between Agglutination and Precipitation

What is Agglutination?

Agglutination refers to the making antigens clump together with their specific antibodies.

Agglutination reactions help fragment test antigens, which are typically coupled to the carrier. The carrier could be made up of (such as charcoal or latex particles) or biological (such as red blood cells). The process of agglutination involving Red blood cells can be known as Hemagglutination. The process that involves the white blood cells can be referred to as leukoagglutination.


The conjugated particles react with the serum of the patient that may or might be devoid of antibodies. The outcome of this test is obtained based on the detection of clumps that result from the antigen-antibody compound creation. The sensitivity and precision of the results are dependent on a variety of variables such as the time of incubation for the antigen, the amount and power of the antigen that is attached to the carrier and the test conditions such as the pH and the protein concentration.

Different types of agglutination can be employed in diagnostic tests that include flocculation tests, latex agglutination tests directly bacterial agglutination and the process of hemagglutination. Since the procedure is fast and easy this diagnostic test is preferred over other tests that are more sophisticated. Agglutination can be utilized to detect antigens in bacteria that ultimately assists to identify these bacteria.


A more sensitive and modified method of Agglutination is agglutination PCR. This technique uses antibodies bind and agglutinate to antigen-DNA conjugates that allow the DNA strands to join to the antibodies. The agglutination resulted is used to determine the size of DNA strands with qPCR.

Examples of Agglutination

Haemagglutination assay

Haemagglutination tests are a diagnostic method used to aid in the identification of bacteria, viruses and antibodies. The antigens found in different bacteria or viruses bind to the sialic acid receptors found in the outer surface of red blood cells, forming the RBCs into a network, as well as viral particles.


The creation of these lattices is dependent on the quantity of virusesor bacteria as well as RBCs. If the concentration of the antigen is not enough the RBCs will not be organized into lattices but fall to on the surface of the vessel.

Haemagglutination works on the same concept similar to the method that viruses employ during their the course of. Control is put within one well in order to determine the antigen concentration on the test sample. On the basis of the amount of agglutination that forms inside the well, amount of the antigen is measured. The concentration of the antigen can be used to determine the amount of the organism that is present within the specimen.


What is Precipitation?

Precipitation occurs when insoluble antigens interact with their particular antibody at the right temperature and pH. This results into the creation of an impervious precipitate.

Interaction between antigen soluble and antibody causes the formation of an insoluble structure which forms precipitate from the solution. This process is subject to some prerequisites that require the valency of both antigen and antibody. In order for precipitation to take place it must be bivalent and the antigen should be polyvalent or bivalent. The precipitation process takes place within the area of equivalence in which the antigen concentration and antibody is the same. In either direction of the equivalence precipitation is not a possibility in the event that the concentration of one antibody or antigen is excessive or insufficient.


Immunological techniques like immunodiffusion and electroimmuno diffusion utilize the principle of precipitation reactions. Principles of precipitation is used in analytical chemistry for the determination of various functional groups in chemical substances. If a more light precipitate forms, a different process known as flocculation occurs. In flocculation the precipitate will float rather than settling.

Precipitation reactions are typically performed on semi-solid materials such as the agar medium or other non-gel support media such as cellulose Acetate. The precipitate produced by the reaction is suspended until a sufficient gravity’s force can bring the precipitate to the lower part of the substrate.


Examples of Precipitation

Immunodiffusion precipitation test

Immunodiffusion is an immunelogical method that is used to detect and measurement of antigens as well as antigens. These are typically immunoglobulins as well as nuclear antigens. In this method, antibodies and antigens are used in parallel wells. Since the antigen and antibodies diffuse toward each other precipitates appear as lines when the antibodies and antigen interact with one another. Also, it is possible to measure the amount of antigens in different concentrations by putting multiple antigens into multiple wells. By observing the development of lines in precipitation the presence of antigens from different sources and, consequently, the presence of bacteria or viruses can be identified.

Differences Between Agglutination and Precipitation – Agglutination vs Precipitation

The Basis of ComparisonAgglutinationPrecipitation
DefinitionAgglutination refers to the making antigens clump together with their specific antibodies.Precipitation occurs when insoluble antigens interact with their own specific antibody at a specific temperature and pH, which results into the creation of an impervious precipitate.
Antigen sizeThe antigen in agglutination tends to be less.The antigen that is involved in precipitation is considerably more powerful.
SolubilityInsoluble antigens are utilized to agglutinate.Antigens that are soluble can be used to precipitate.
SensitivityAgglutination reactions are more sensitive than precipitation reactions.Precipitation reactions are more sensitive than agglutination reactions.
PrincipleAgglutination relies on the idea of formation of clumps of particles.Precipitation is based on idea of the development of lattices (cross-linkages).
Reactions that are involvedAgglutination is a complex chemical reaction that results in complex formation.Precipitation is the result of chemical reactions between salt molecules and ions.
MediaThere is no need for a gel matrix to agglutinate.A semi-solid or liquid matrix is required for precipitation.
Resulting compoundAgglutination leads to the creation of agglutinates.Precipitation causes precipitates forming.
The nature of the complex that formedThe agglutinins typically settle to the base of the container.The precipitins may remain suspended or fall toward the bottom. In flocculation, the flocculants are floating in the water matrix.
Reactants’ natureThe molecules used in the initial stages of Agglutination are essentially particles.The molecules that precipitate the first time are Ions.
RequirementsAgglutination reactions occur on the surface which means that the antigen’s surface have to be exposed in order for the antibody to be able to bind and form visible clusters.The amount of antigen and antibody must be the same. Any deviation from this equilibrium hinders precipitins from forming.
Reaction timesAgglutination reactions can take anywhere from between minutes and hours to complete.The precipitation reaction can occur within the hours or days.
AppearanceThe products that result from Agglutination reactions are visible as large visible aggregates.The precipitation products that result from the reaction are large, visible and insoluble aggregates.
ApplicationsAgglutination reactions can be useful for blood grouping.Precipitation reactions can be useful for qualitative analysis and in the formation of pigments.

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