Is a 4ml decrease in testicular size from 14ml to 10ml over 6 weeks, with an elevated Follicle-Stimulating Hormone (FSH) level of 10.4 and a sperm count of 80 million/ml, a cause for concern regarding testicular function or fertility?

Testicular Volume Measurement Variability

A 4ml decrease in testicular volume from 14ml to 10ml over 6 weeks is almost certainly due to measurement error rather than true biological change, as adult testicular volume does not fluctuate this rapidly without acute pathology. 1

Understanding the Measurement Discrepancy

The reported volume change is technically implausible and reflects inter-observer variability or inconsistent measurement technique rather than actual testicular atrophy. True biological change in testicular size over 4-6 weeks is extremely unlikely in adults unless there is acute pathology such as testicular torsion, trauma, or orchitis. 1

Technical Sources of Error

• Testicular volume measurements using ultrasound or orchidometer are subject to significant inter-observer variability, with differences of 2-4ml being common between measurements. 1
• The most common technical errors include incorrect caliper placement during ultrasound, measuring at different testicular axes, and using different measurement formulas (the 0.52 ellipsoid formula systematically underestimates volume by 20-30% compared to the 0.71 Lambert formula). 1
• Different sonographers or use of different measurement techniques between the two assessments can easily account for a 4ml discrepancy. 1

Recommended Approach to Clarify True Volume

• Request a repeat scrotal ultrasound with explicit attention to proper measurement technique, using high-frequency probes (>10 MHz) and the Lambert formula (Length × Width × Height × 0.71) for volume calculation. 1
• The same sonographer should perform serial measurements when possible, or measurements should be remeasured on previous scans by the current operator to minimize inter-scan variability. 1
• Compare measurements to the contralateral testis, as size discrepancy greater than 2ml or 20% warrants further evaluation to exclude pathology. 1

Interpreting Your Hormone and Fertility Parameters

FSH Level of 10.4 IU/L

Your FSH of 10.4 IU/L is mildly elevated and indicates some degree of testicular dysfunction, but does not preclude normal sperm production. 2

• FSH levels >7.6 IU/L are associated with a five- to thirteen-fold higher risk of abnormal sperm concentration compared to men with FSH <2.8 IU/L, but this represents reduced counts, not necessarily azoospermia. 2, 3
• The elevated FSH with preserved sperm count of 80 million/ml indicates your hypothalamic-pituitary-gonadal axis is compensating for mild testicular dysfunction by increasing FSH output to maintain adequate spermatogenesis. 2
• FSH levels alone cannot definitively predict fertility status—up to 50% of men with non-obstructive azoospermia and elevated FSH still have retrievable sperm, so your situation with preserved sperm production is entirely consistent with this FSH level. 2

Sperm Count of 80 Million/ml

Your sperm concentration of 80 million/ml significantly exceeds the WHO lower reference limit of 16 million/ml and indicates preserved spermatogenic function despite the mildly elevated FSH. 2, 4

• This sperm count places you well within the normal fertile range and suggests that despite mild testicular dysfunction (reflected by elevated FSH), your testes are producing adequate numbers of sperm. 4
• The combination of mildly elevated FSH with normal sperm count is the classic pattern seen in compensated testicular dysfunction, where the pituitary increases FSH output to maintain normal sperm production. 2

Clinical Significance and Monitoring

What This Means for Your Fertility

• Your current fertility parameters are reassuring, with sperm count well above the threshold associated with good natural conception rates. 4
• The mildly elevated FSH indicates reduced testicular reserve, meaning you have less capacity to compensate if additional stressors occur (such as illness, medications, or environmental exposures). 2
• Men with borderline-small testes (10-14ml range) and elevated FSH are at higher risk for progressive spermatogenic decline over time. 1

Essential Next Steps

• Repeat semen analysis in 3-6 months to establish whether sperm parameters are stable or declining, as single analyses can be misleading due to natural variability. 4
• Measure complete hormonal panel including LH and total testosterone to determine if this represents primary testicular dysfunction (elevated LH) versus secondary causes. 2, 4
• Consider sperm cryopreservation as a protective measure if you plan to delay conception, especially if follow-up semen analyses show a declining trend. 2

Critical Pitfalls to Avoid

• Never start exogenous testosterone therapy if current or future fertility is desired, as it will completely suppress spermatogenesis through negative feedback, potentially causing azoospermia that can take months to years to recover. 2
• Do not assume the testicular volume measurements are accurate without confirmation using standardized technique—request repeat measurement if clinical decisions depend on this value. 1
• Address potentially reversible causes of elevated FSH, including thyroid dysfunction, metabolic stress, obesity, and environmental exposures, as optimization may improve hormonal parameters. 2