Monitoring ovarian function by a solid-phase chemiluminescence immunoassay

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Abstract
Ovarian function in women may be monitored by a simple, solid-phase, chemiluminescence immunoassay for the measurement of estrone-3-glucuronide in diluted urine. An IgG fraction of antiserum to estrone-3-glucuronyl-6-bovine serum albumin is passively adsorbed to the walls of polystyrene tubes. Estrone-3-glucuronyl-6-aminoethyl-ethyl-isoluminol is the labelled antigen. Daily samples of early morning urine [EMU] are diluted in buffer (1:100; vol/vol), and 100 .mu.l removed, in duplicate, for assay. After the binding reaction (1 h at 4.degree. C), the solution is removed by aspiration. The antibody-bound fraction is washed once with buffer (400 .mu.l). Sodium hydroxide (2 N, 200 .mu.l) is added and the mixture incubated for 60 min at 22.degree. C. Luminescence is initiated by oxidation of the label with microperoxidase/hydrogen peroxide and the signal integrated for 10 s. An evaluation of the method gave the following values: sensitivity of calibration curve 3.12 .+-. 0.75 pg/tube (mean .+-. SD). The intra-assay precision (CV%) was 9.52 (20 replicates; 38.4 .+-. 3.66 nmol/l) and 8.61 (15 replicates; 102.4 .+-. 8.82 nmol/l). The inter-assay precision (CV%) was 11.9 (mean of 4 pools -7.03, 23.16, 52.11 and 117.53 nmol/l over 2 mo.). The mean bias was -0.78% over the range 28 to 448 nmol/l and different aliquots (equivalent to 0.25-4 .mu.l) of daily EMU gave results that were in good agreement. The concentration (nmol/l; mean .+-. SD) of estrone-3-glucuronide in samples of EMU collected from healthy women during the early follicular, periovulatory and luteal phases of the menstrual cycle were 40.2 .+-. 9.9, 102.3 .+-. 39.4 and 84.3 .+-. 13.3 nmol/l, respectively. In addition, the results obtained from the analysis of EMU throughout 6 complete menstrual cycles were in good agreement with the values derived by radioimmunoassay (r = 0.94).