Most rapid diagnostic tests work by capturing analytes on a solid surface and then attaching molecules to them that allow detection by the naked eye. “Analyte” is a very broad term describing molecules which are indicative of various states, such as infection, pregnancy, high cholesterol, etc. There are two primary types of analyte, antibodies and antigens. Antibodies are a specific class of molecules which are created by a person’s immune system in response to an infection. Thus, antibody detection tests detect a patient’s immune response resulting from infection and are thus useful for diagnosing infectious diseases. The term “antigen” is a general term that is applied to analytes that are not antibodies. Antigen detection tests detect biomarkers that are not related to the patient’s immune response. Antigen detection tests are useful for diagnosing infectious diseases as well as various other states that do not elicit an immune response such as high cholesterol, drug use, etc. The test procedure is generally the same regardless of whether antigens or antibodies are detected by the test.

There are a few basic test formats offered by manufacturers. These include:

Basic test formats. Lateral-flow Flow-through Agglutination Solid phase