In the laboratory, ELISA is used to quantitatively measure or qualitatively detect any number of different target antigens. ELISAs are able to detect and quantify a wide variety of antigenic targets including peptides, proteins, antibodies, hormones, and small molecules.
When choosing an ELISA kit, most researchers demand an assay that is sensitive, specific, and highly-validated.
A sensitive assay is able to detect antigen at a very low titer in sample matrix (sometimes as low as pg/mL). A specific assay measures the target antigen only, and does not cross react with other common components inside normal sample matrices. A validated assay is accompanied by a sufficient quantity of data to confirm that both the sensitivity and specificity of the assay are consistent with the advertised specifications.