Sensitive ELISA for determination of serum E2 using a new tracer E2-Biotin

A new tracer conjugate of E2-Biotin, with different spacers, was synthesized at position 3 in the estradiol molecule for first time. Immunoreactivity of the tracer was determined by reacting with the anti-E2 monoclonal antibody. The monoclonal antibodies raised against E2 were characterized for its use in ELISA detection systems of serum E2. The purified antibody has a high affinity and specificity for E2. The antibody and tracer were used for establishing a competitive ELISA for estradiol (E2). The experimental results showed that the dose-response curve of the assay covered a range of 33-20,000 pg/mL (n = 8). The detection limit is 28.3 pg/mL (S/N = 3). The intra- and inter-assay coefficients of variation for the assay of serum samples ranged from 5.7 to 13.2% and from 5.3 to 10.6%, respectively. Precoated microtiter plates were dried at 4 degrees C and they were stable for up to 3 months.