RESUMO
Luteinizing hormone (LH) is a dimeric glycoprotein produced and secreted by the pituitary gland, with a molecular weight of approximately 30 000 Da. The main clinical use for exogenous LH-administration is typically linked to the treatment of infertility, in both men and women. The desired effect of LH misuse in sport is due to the enhancement of testicular production of testosterone. Elevated LH levels may also indicate the usage of gonadotropin-releasing factors or estrogen blockers. Therefore, LH is listed by the World Anti-Doping Agency (WADA) as a prohibited substance in male athletes, and according to the WADA technical document, laboratories should determine the the total LH concentrations in urine. The TD lists two different assays that are suitable for measuring total LH in urine, Delfia and Siemens Immulite. Other fit-for-purpose assays can be used, as long as they are capable of detecting total LH in urine. In case an assay not listed in the TD will be used, population-based reference values have to be determined in the validation procedure. In this study a new immunoassay was validated for the measurement of LH in urine. The assay (AccuBind ELISA Microwells, Luteinizing Hormone, Monobind Inc.), originally intended for serum, showed adequate sensitivity and was proven fit-for-purpose in routine doping control. Population-based distribution of the assay was in good agreement with the results of Delfia and Immulite assays, for which the method-specific cut-off-values are 40 IU/L (Delfia) and 60 IU/L (Siemens Immulite).
