IVD kits contain everything necessary to perform a specific test, including the reagents, key consumables, and a highly optimised protocol. The researcher simply provides the sample material and runs the assay as described to produce clear and informative data. Since kits are usually supplied in an easy-to-use format, they can streamline workflows and reduce potential experimental variability. Like IVD antibodies, kits intended for IVD use are subject to stringent regulatory control.

Well-known IVD kit formats include ELISA, lateral flow and IHC, and these have more recently been complemented by kits designed for DNA or RNA detection. During an ELISA, the target antigen may be captured from the test sample by an antibody which has been immobilised on a microplate (sandwich ELISA). Alternatively, antibodies contained within the sample material can become bound by immobilised antigen (direct ELISA). Lateral flow immunoassays work on a similar basis, however, the immobilised reagent is instead bound to a test strip; as the sample flows along the test strip, the target molecule is captured to generate a visible readout.

IVD kits for IHC pathology are used to stain tissue samples for detection and localisation of an antigen. Kit components vary depending on the nature of the target (e.g. an antigen retrieval step may be necessary), the type of antibodies required for detection (e.g. directly conjugated primary antibodies versus secondary antibodies) and the readout (e.g. fluorometric or colorimetric). Nucleic acid-based tests are available in a range of formats; they may be used to detect the presence of an infectious agent, identify a specific mutation, or perform genotyping.