SPACE-RESOLVED FLUOROIMMUNOASSAY FOR QUANTIFYING ALPHA-FETOPROTEIN INSERUM

A nickel-coated surface was used to adsorb a monolayer of anti-human a lpha-fetoprotein antibody. After incubation with a patient's serum, th e sample was stained with fluorescein isothiocyanate (FITC)-conjugated anti-human alpha-fetoprotein antibody. These slides were then read wi th, a Space-resolved fluorometer to determine the amount of FITC adsor bed onto the metal surface. We used an argon laser as the light source in the fluorometer. The parallel laser beam was tilted at about 45-de grees to the sample surface. The fluorescence from FITC was read with a perpendicular photon counter to reduce noise. The CV for these tests was approximately 10%. Comparison of these results (y) with those of a conventional radioimmunoassay (x) produced the regression equation y = 0.99x + 0.5, over the range 10-140 mug/L (n = 51).