A prototype for ovulation detection: pros and cons.

A noninstrumented enzyme immunoassay for urinary estrone conjugates was adapted from an instrumented microtiter plate enzyme immunoassay assay. The end point of the assay was a color change from green to clear, which was visible to the unaided eye. The visible color change was adjusted to allow 80 ng/ml estrone conjugates (on the basis of a sample size of 6.5 microliters urine) to be distinguished from an infinite dilution without instrumentation. The evaluation of human urine collected from ovulatory ovarian cycles demonstrated that early follicular phase concentrations (35.9 +/- 6.8 to 79.4 +/- 14.7 ng/ml, n = 10) produced a dark-green color, whereas late follicular phase concentrations (162.9 +/- 20.1 ng/ml, n = 10) produced no color. Daily urine samples throughout 10 ovulatory ovarian cycles produced parallel profiles when compared to measurements of estradiol in paired blood samples. Complete analysis of the data indicated that ovarian follicular dynamics can be accurately monitored through the noninstrumented analysis of daily estrone conjugates in urine samples.