Difference Between Agglutination and Precipitation

The solution is a mixture that consists of two or more two substances. It is a homogenous mixture. A solute is a substance that gets dissolved in a solvent. Like sugar is a solute, and water is a solvent. When solute gets dissolved in a solution, it cannot be seen with bare eyes. The solution is a stable thing and cannot be filtered. It occurs in only one phase.

Agglutination and Precipitation forms a solid mass inside a solution. This solid mass can either get dissolved or will stay in suspension. Both are very different processes that happen due to complex chemical reactions.

Agglutination vs Precipitation

The main difference between Agglutination and Precipitation is that Agglutination is a process where a solid mass is formed inside a solution from the particles present there. Whereas Precipitation is a process of forming a solid mass that is insoluble from the ions present in a solution. Agglutination is a complex process that involves reaction. Precipitation is a chemical reaction where salts and ionic compounds are formed. The procedure in agglutination is more sensitive than the procedure in Precipitation.

Agglutination vs Precipitation

Agglutination means when there is an accumulation of particles or when the particles get clumped together. When an antigen is mixed with its antibody than the process is called isoagglutinin. The term isoagglutinin is a very common term in blood grouping. When all the particles accumulate to form a single large mass. That mass will either stay in suspension, or it will sink in the bottom but not get dissolved. The end product is always aggregate. Agglutination only happens if there are already some particles present inside a solution.

Precipitation is a process where precipitate is formed when there is a formation of an insoluble molecule in a liquid solution. The chemical reagent that is responsible for leading the reaction and turning it into solid mass is called a precipitate. The liquid that is above the precipitate is clear and is called supernate. Precipitation can be applied to other fields as well other than chemistry, like it can be used in alloys and metallurgy to remove the solid impurities from the solid phase. Precipitation depends upon factors like temperature change, mixing solvents, evaporation of solvents etc.

Comparison Table Between Agglutination and Precipitation

Parameters of ComparisonAgglutinationPrecipitation
SizeSmaller antigenLarger antigen
TypesActive and passive agglutinationPrecipitation in solution, precipitation in diffusion and electrophoresis.
UsesBlood GroupingQuantitative analysis, Pigment formation etc.
Matrixmicrotitre plate, glass slides and test tubes.Test tubes, glass slides, Petri plates.

What is Agglutination?

Agglutination was discovered by two bacteriologists, namely Herbert Edward Durham and Max von Gruberin 1896. Gruber was the one who gave the term agglutinin. Together the clumping process was called the Gruber-Durham reaction. Agglutination was first used as a base for a test of typhoid fever. This kind of test was the first that helped in the serum diagnosis. Karl Landsteiner was another physician who, in 1900, discovered another practical application of agglutination that led to the discovery of the ABO blood group. This helped humanity to start the process of blood transfusion and serology.

Agglutination is also called the antigen-antibody process, where the soluble antigen reacts with antibodies to form agglutinin. It is a sophisticated and sensitive process as it requires the handling of particulate antigens. Particles present in the solution in the process of agglutination is the starting product. Agglutination forms a solid mass in the solution, and unlike in precipitation, it gets sinks at the bottom of the container.

A smaller size of compounds is needed to carry out the process of agglutination. The reaction of agglutination takes place in a broad spectrum. Because there is clumping and cross-linkage between the particles and antibodies. The end product in agglutination can appear as large aggregates. It is very easy to perform agglutination. They are soluble as well.

What is Percipitation?

Precipitation is a chemical reaction that is linked with the antibody to form ions in the solid form. The product formed is called a precipitate. When soluble salts are bound together to form an insoluble precipitate in an aqueous solution, then it is called Precipitation. The reaction occurring between salts and ionic compounds also result in precipitation. Antigen in precipitation is bigger and larger. The resulting or the end product is called precipitin.

Precipitation is used in many processes like quantitative analysis, water treatment techniques, and pigment formation. Solubility of Precipitation is insoluble. Precipitation needs gel or any type of liquid to happen. The reaction of precipitation can be performed on glass tubes, test tubes, or Petri dishes. The end product in Precipitation is visible in the form of crystalline ionic solids.

Valency plays an important role in taking up precipitation. If both antigen and antibody are bivalent or polyvalent, then the reaction will take place. It takes place when both are in equivalence. If there is excess or deficit in antigen or antibody, precipitation will not occur. It is used in analytical chemistry to detect various chemical substances.

Main Differences Between Agglutination and Precipitation

  1. In Aggulitination, the size of the antigen is smaller. In precipitation, the size of the antigen is larger.
  2. An antigen is sedimented in the form of Agglutination. An antigen is in soluble form in precipitation.
  3. Types of agglutination include active and passive agglutination. Types of Precipitation includes precipitation in solution, precipitation in diffusion and electrophoresis.
  4. The use of agglutination is blood grouping. Uses of precipitation are quantitative analysis, water treatment techniques, and pigment formation.
  5. Agglutination can be performed on glass slides, test tubes and microtitre plates. Precipitation can be performed on Petri places, glass sides and test tubes.


Both Aggulutination and Precipitation are used in several chemical reactions, including inorganic and biological analysis as a detection method. Agglutination is very important in biology. Whereas Precipitation is very important in chemistry. Both of them have the same outcomes, but there is a certain difference between them that is visible, like in agglutination, solid mass sinks in the bottom. While in precipitation, it can either suspend or sink.

Agglutination is based on the clumping of particles. While Precipitation is based on the formation of lattices. In agglutination, there is no gel matrix, while in precipitation, there is a liquid or gel matrix. Agglutination reaction takes less time, from minutes to hours. But precipitation can take a long time, from hours to days.


  1. https://www.jimmunol.org/content/18/5/393.short
  2. https://rupress.org/jem/article-abstract/46/2/303/9635
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