What is an Immunochromatographic Assay?

An immunochromatographic assay (also known as a lateral flow test) is a device used to detect the presence or absence of a specific analyte within a sample. These instruments consist of a number of capillary beds, which can transport a fluid spontaneously. The capillary beds can be either a piece of porous paper, sintered polymer, and microstructured polymer.

The first capillary bed acts as the sample bed and holds an excess amount of the sample being tested. When this capillary bed is soaked, the fluid transfers to the second bed that holds the conjugate, which is a dried format of bio-active particles in a salt-sugar matrix. This bed contains everything required to ensure the chemical reaction takes place between the target molecule and the chemical that is immobilized on the surface of the particle.

When applied to the immunochromatographic assay, the sample dissolves the salt-sugar matrix, the particles, and the sample mixes with the conjugate. It is through this process that the target molecule binds to the particles, before being transported to the third capillary bed.

This bed often consists of multiple areas with an immobilized molecule. Typically there are two areas (also known as stripes); the first stripe only changes color if the target analyte is detected.

The second stripe is a control that changes color with any particle, and is used to indicate that the technology is working.

When the mixture of the sample and the conjugate reaches the third capillary bed in an immunochromatographic assay, the analyte is bound to the particle, and the immobilized molecule binds the complex. As more of the sample is transported to the third capillary bed, the areas change color.

There is an extensive range of benefits associated with immunochromatographic assays. Firstly, they are relatively inexpensive and readily available, making them an accessible instrument. They are also very simple to use and provide a result in a short amount of time.

Immunochromatographic assays find use in a wide range of applications and are most commonly employed for medical applications. A pregnancy test is the most common use of immunochromatographic assays, but they are also used to detect drugs-of-abuse and therapeutic drugs.

Pyxis Laboratory supply a range of immunoassay reagents that can be used for immunochromatographic assays. Our lot-to-lot reproducibility is unmatched, and our scientists are all experts in their fields.

If you would like any more information about how Pyxis can help with the reagents needed for the manufacture of immunochromatographic assays, please contact us