RAPID ENHANCED CHEMILUMINESCENT ENZYME-IMMUNOASSAY FOR FERRITIN MONITORED USING INSTANT PHOTOGRAPHIC FILM

A rapid chemiluminescent enzyme immunometric assay (EIA) for serum ferritin has been developed which combines a halophenol-enhanced chemiluminescent assay for the peroxidase label with photographic detection (20000 ASA instant film) of light emission. Assays were performed using a microtitre plate as the solid support and a specially designed camera luminometer to measure light emission from individual antibody coated wells. The assay operates as a threshold test: above a certain serum ferritin concentration the film was fully or partially exposed whilst below this level the film remained unexposed. The effect of incubation time and temperature were investigated and two rapid immunoassays were developed. In one, a 10-min incubation with sample and with conjugate detected 1 ng (10-mu-g l-1) of ferritin, whilst in the other, 3-min incubations at ambient temperature detected 40 ng (400-mu-g l-1) of ferritin. These assays were reliable, produced a permanent photographic record of the results and the fastest assay was completed in less than 10 min.