A comparison of the sensitivity and specificity of enzyme immunoassays and time-resolved fluoroimmunoassay

Abstract Time-resolved fluoroimmunoassay (TR-FIA) and various enzyme immunoassays (EIA) were compared in order to determine the detection system which showed the greatest degree of sensitivity without sacrificing specificity. The system chosen for the evaluation of these assays was the detection of antibodies to human immunodeficiency virus (HIV). For EIA, horseradish peroxidase (HRP) and alkaline phosphatase (AP) were investigated, each with a number of different substrates. HRP with its fluorogenic substrate, 3-( p -hydroxyphenyl)propionic acid (HPPA) was 1.6 times ( p p p p p -nitrophenyl phosphate (pNPP). TR-FIA with Eu 3+ -labelled anti-human IgG was equivalent in sensitivity to HRP with TMB and AP with 4MeUP.