Determination of median levels of the free β subunit of human chorionic gonadotropin in women from mainland China using a new time-resolved fluoroimmunoassay

Abstract

Article in press -uncorrected proof Determination of median levels of the free b subunit of human chorionic gonadotropin in women from mainland China using a new time-resolved fluoroimmunoassay ) chelates only. Methods: We developed a two-site, one-step assay using two monoclonal antibodies (MAbs) against free b subunit and b subunit with Eu 3q chelates as labels. Using the present assay, we evaluated 24,634 normal serum samples in Chinese pregnant women during 8-20 weeks of gestation. Results: The detection limit using this assay was -0.05 ng/mL. The within-run and between-run imprecision was -6.0% and 7.0% using control material. Free b-hCG concentrations measured using the current assay in 999 maternal serum samples correlated well with those obtained by samarium (Sm 3q )-labeled DELFIA free hCGb assay (rs0.987). The medians for 8-20 weeks for maternal serum free b-hCG were higher in the women from mainland China compared to reports from other countries. Conclusions: The present assay is suitable for use in biochemical screening of women in mainland China. Our study on the median concentrations of free b-hCG will help establish reference values that are specific for ethnic populations from the Chinese mainland. These will be useful for studying the importance of ethnic factors in biochemical screening.

Pituitary as a Source of HCG: Residual Levels After Bilateral Testicular Tumor Removal

“…24 However, heterophile antibodies and other substances can interfere with HCG assays, but in our patient results from serial dilution of the serum and incubation with heterophile blocking tubes suggest that the elevated HCG levels were not due to interference. 13,29…”

“…(2) In men with bilateral orchiectomy, the LH and FSH levels may not be suppressed when exogenous testosterone is administered, 18,19 when this occurs after chronic orchiectomy. (3) Recent assays no longer exhibit cross-reactivity between LH and HCG, 29,30 but heterophile antibodies, biotin, and other substances can interfere. (4) There are a number of tumors that make HCG 22,23 as reviewed several years ago by Glenn Braunstein et al (5) The metabolic clearance rates of testosterone are variable, 15 and a low metabolic clearance rate will result in a high testosterone level in men with no testes when given a standard dose of testosterone.…”

“…24 However, heterophile antibodies and other substances can interfere with HCG assays, but in our patient results from serial dilution of the serum and incubation with heterophile blocking tubes suggest that the elevated HCG levels were not due to interference. 13,29 Rapid electronic communications facilitate the utilization of experts in the management of difficult or confusing clinical cases. The evaluation of this patient represents an excellent example of this phenomenon.…”