Establishing reference intervals for hCG in postmenopausal women

Area of Science:

• Reproductive Endocrinology
• Clinical Chemistry
• Geriatric Medicine

Background:

• Plasma human chorionic gonadotropin (hCG) concentrations may increase with age due to pituitary secretion.
• A previous recommendation suggested an hCG cutoff of 14.0 IU/L for women aged 55 years and older.
• The occurrence of hCG concentrations above 14.0 IU/L in advanced age remained uncertain.

Purpose of the Study:

• To establish plasma hCG reference intervals in postmenopausal females aged 55 years and older.
• To correlate follicle-stimulating hormone (FSH) and hCG concentrations in this demographic.
• To evaluate the validity of the 14.0 IU/L hCG cutoff in older women.

Main Methods:

• Analysis of residual plasma samples from 798 women aged 55 years and older, stratified into age groups (55-69, 70-84, ≥85).
• Measurement of FSH and hCG using the Abbott ARCHITECT assay.
• Exclusion of samples with potential heterophile antibody interference and patients with malignancy.

Main Results:

• 8% of women aged ≥55 years exhibited plasma hCG ≥5 IU/L.
• The highest observed hCG concentrations and 97.5th percentiles varied across age groups, with the overall 97.5th percentile for women ≥55 years being 8.5 IU/L.
• Neither hCG nor FSH concentrations demonstrated a consistent increase with advancing age in women ≥55 years.

Conclusions:

• The prevalence of positive hCG (≥5 IU/L) in women aged ≥55 years is 8%.
• The study reaffirms the previously recommended hCG cutoff of 14.0 IU/L for women aged 55 years and older.
• Follicle-stimulating hormone (FSH) concentrations do not predict hCG concentrations in postmenopausal women aged 55 years and older.