A simple dipstick immunoassay for detection of A and B antigens

ABH antigens, by virtue of their stability and widespread distribution are of unique significance in forensic examination. The conventional methods of typing often lack sensitivity and specificity. They fail to provide dependable results when samples are of minute size and exposed to harsh climatic conditions. We have developed a simple, rapid and highly sensitive solid phase double antibody dipstick immunoassay for detection of A&B antigens by using A&B antibodies (Human) immobilized on nitrocellulose membrane (NCM) strips. The bound antigens have been probed by enzyme labelled second antibodies (Mouse monoclonals). The dipstick assay successfully detected A&B antigens in stains containing as little as 100 ng of dried blood. Bloodstains as old as two years could be correctly typed by this method. The assay has the added advantage of simplicity and rapidity. A and B antigens found in tissues, saliva, urine, or sweat can also successfully be detected by the assay. Contaminated bloodstains that conventional methods failed to detect were also identified by this assay.