Serum hCG reference values in menopausal women across four immunoassay platforms: implications of renal function for clinical interpretation

Objectives Most available data on human chorionic gonadotropin (hCG) elevations in menopausal women are derived from studies using Roche assays, with limited evidence across other immunoassay platforms. This study aimed to establish assay-specific reference values for hCG and evaluate the impact of age and renal function. Methods In this prospective study, 300 women were divided into five groups (n=60 each): perimenopausal (40–54 years), three postmenopausal age groups (55–69, 70–84, ≥85 years; all with estimated glomerular filtration rate [eGFR] ≥15 mL/min), and postmenopausal women with end-stage renal disease (ESRD; eGFR <15 mL/min). Serum hCG was measured on four automated platforms (Atellica ® IM, Liaison ® XL, Alinity ® i, Roche cobas ® ). Reference thresholds were defined for each subgroup using the maximum observed hCG value. Results hCG levels correlated positively with age and gonadotropins and negatively with renal function. In women <55 years, values were consistently <5 IU/L. Among postmenopausal women (eGFR ≥15 mL/min), hCG concentrations were higher in those ≥85 years than in the 55–69 and 70–84 groups; however, this difference disappeared when analyses were restricted to women with preserved renal function (eGFR ≥60 mL/min). Reference values were therefore stratified according to renal function. Proposed cutoffs were 10 IU/L for eGFR ≥60 mL/min and 15 IU/L for eGFR 15–59 mL/min, regardless of the analytical method. In patients with eGFR <15 mL/min, assay-specific cutoffs ranged from 18 to 36 IU/L. Conclusions Renal function is a major determinant of hCG elevation in menopausal women. Renal function-stratified reference thresholds improve the accuracy of clinical interpretation.