Various forms exist, including enzyme-linked immunosorbent assay (ELISA) and fluorescent enzyme immunoassay (FEIA). The competitive hybridization assay is similar to a traditional competitive immunoassay. Radioactive isotopes can be incorporated into immunoassay reagents to produce a radioimmunoassay (RIA). The laboratory testing usually involves immunoassay or liquid chromatography-mass spectrometry. EIA (enzyme immunoassay) detects antibodies using a DNA-coated polystyrene microtitre plate. The company produced and distributed immunoassay platforms and high performance monoclonal antibodies. Early detection of pancreatic cancer biomarkers was accomplished using SERS-based immunoassay approach. Heterophile antibodies can cause significant interference in any immunoassay. Protein microarrays are a type of immunoassay that often employ fluorogenic reporters. Cardiac troponin T and I are measured by immunoassay methods. Point of care (e.g., doctor's office) devices use immunoassay ororonate affinity chromatography. The most common method of drug detection is an immunoassay. BTA-STAT is a dipstick immunoassay for detection of human complement factor H-related protein. Urine drug testing is an immunoassay based on the principle of competitive binding. Direct determination of the thymidine kinase protein by immunoassay has also been used.