Distribution and Positive Predictive Value of Follicle Stimulating Hormone Among Nonazoospermic Men

Area of Science:

• Reproductive Endocrinology
• Andrology
• Clinical Diagnostics

Background:

• Follicle stimulating hormone (FSH) plays a crucial role in spermatogenesis.
• Assessing FSH levels is common in male fertility evaluations, but its predictive value for fertility status requires clarification.

Purpose of the Study:

• To characterize FSH distribution in fertile versus subfertile nonazoospermic men.
• To evaluate the efficacy of various FSH thresholds in predicting male fertility status.

Main Methods:

• Retrospective cohort study of 1389 nonazoospermic men undergoing fertility evaluation.
• Men classified as fertile or subfertile based on total motile sperm count.
• Analysis of FSH levels and calculation of positive predictive values (PPVs) for different FSH thresholds.

Main Results:

• Median FSH was significantly higher in subfertile (6.0 mIU/mL) compared to fertile men (4.0 mIU/mL).
• FSH thresholds between 2.2 and 9.3 mIU/mL demonstrated poor predictive value for subfertility (PPV 0.49-0.59).
• Only FSH levels above the 95th percentile (12.1 mIU/mL) offered clinically useful predictability for subfertility.

Conclusions:

• Standard FSH cutoffs are insufficient for accurately predicting fertility status in nonazoospermic men.
• High FSH values, particularly those in the 95th percentile and above, are more indicative of subfertility.
• FSH testing is valuable but should not be used as a standalone fertility test; extreme values or discordant results warrant further investigation.