Development and evaluation of a direct immunofluorimetric assay for urinary growth hormone

We describe a two-site immunofluorimetric assay for urinary growth hormone that is resistant to interference from a wide range of urinary constituents and therefore eliminates the need for sample pre-treatment. A microtitre p late format is used with specific orientation of capture antibody on a poly styrene surface carrying a hydrazide group. Europium-labelled F(ab)(2) is t he fluorophore and time-resolved fluorimetry with co-fluorescence enhanceme nt the signal detection system. Inter-assay precision was 11.3% at 5.2 ng/L and 10.3% at 44.3 ng/L, minimum detection limit (22% coefficient of variat ion, CV) was <1.0 ng/L, working range (<10% CV) was 0-100 ng/L and quantita tive recovery and good parallelism were demonstrated. This convenient and s ensitive assay is suitable for the routine measurement of human growth horm one (hGH) in urine.