A time-resolved fluoroimmunoassay for cortisol in unextracted bovine plasma or serum with optimized procedures to eliminate steroid binding protein interference and to minimize non-specific streptavidin–europium binding

摘要: Abstract A time-resolved fluoroimmunoassay (TR-FIA) for human salivary cortisol was adapted the measurement of in unextracted bovine blood plasma and serum. It has been demonstrated that binding proteins (CBPP) to cortisol–biotin primary probe cannot be eliminated by means releasing agents. Complete inactivation CBPP achieved heating water diluted samples 30 min at 80°C. The high non-specific (NSB) streptavidin–europium secondary probe, encountered during preliminary experiments, shown caused an interaction with serum albumin (BSA) could reduced partly addition heparin. also ability bind nonspecifically is not a general property since γ -globulin gelatin lack this behaviour. advantage highly NSB, resulting from use BSA free assay buffer, limited particular but beneficial other procedures based on specific fluorescence. detection limit 20  μ l sample 0.5 ng/ml. intra-assay coefficients variation control concentrations 71.1, 39.2 10.3 ng/ml were 8.2, 7.9 11.3% ( n =16). corresponding inter-assay 7.3, 9.0 11.2% =73). Correlation commercially available radioimmunoassay, preceded diethylether extraction sample, 0.97 =88).