Measurement of estrone-3-glucuronide in urine by rapid, homogeneous time-resolved fluoroimmunoassay

We describe a liquid-phase nonseparation time-resolved fluorescence immunoassay for measuring estrone-3-glucuronide in undiluted urine. The sensitivity, specificity, and accuracy are similar to those for a conventional separation fluoroimmunoassay or radioimmunoassay, but the speed, convenience, precision, reliability, and clinical utility of the new method are more advantageous. The labeled antigen, a fluorescent europium chelate covalently linked to estrone-3-glucuronide, is incubated for 10 min with a limited concentration of polyclonal or monoclonal antibodies to estrone-3-glucuronyl-6-bovine serum albumin and 10 microL of standard or sample (undiluted urine) in microtiter wells. The fluorescence emanating from the antibody-free label, which is proportional to the concentration of estrone-3-glucuronide in the standard or sample, is then measured in a time-resolved fluorometer. The method is useful for monitoring ovarian function in women.