Detection of the products of the PCR reaction using nonisotopically labeled DNA molecules containing biotin, fluorescein, or digoxigenin has become a popular method for identification of specific products of polymerase chain reaction (PCR) (1 ,3 ). These labeled molecules are prepared either by PCR synthesis in the presence of labeled deoxyuridine triphosphate (1 ,3 ) or by hybridization of labeled probes to the unlabeled PCR product (1 ,2 ). Detection is then in a format very similar to enzyme-linked immunosorbent assays (ELISA) using similarly labeled antigens and antibodies, i.e., by capture on the receptor for one ligand (streptavidin or antibody) and using the other ligand for detection.
