What laboratory tests are used to assess male fertility?

Laboratory Tests for Male Fertility Assessment

The initial screening for male fertility should include a reproductive history and two semen analyses performed at least one month apart. 1

Initial Laboratory Evaluation

Semen Analysis

Semen analysis is the cornerstone of male fertility assessment and should include:

• Volume: 1.4-5.0 mL (lower reference limit: 1.4 mL)
• pH: >7.2
• Sperm concentration: >16 million/mL (lower reference limit)
• Total sperm number: >39 million per ejaculate
• Motility:
  • Progressive motility: >30%
  • Total motility: >42%
• Morphology: >4% normal forms
• Vitality: >54% live sperm

1, 2

Collection Instructions

• Abstain from sexual activity for 2-3 days before collection
• Collect by masturbation or intercourse using specialized collection condoms
• Keep specimen at room or body temperature during transport
• Examine within one hour of collection 1

Important Considerations

• Semen parameters are highly variable biological measures
• At least two analyses should be performed, especially if the first shows abnormal parameters
• Point-of-care and mail-in tests may provide some information but are not substitutes for laboratory analysis 1

Additional Laboratory Testing

Endocrine Evaluation

Perform endocrine evaluation if:

• Sperm concentration <10 million/mL
• Sexual function is impaired
• Clinical findings suggest endocrinopathy

Minimum initial endocrine evaluation:

• Serum testosterone
• Serum follicle-stimulating hormone (FSH) 1, 2

Post-Ejaculatory Urinalysis

Indicated when:

• Ejaculate volume <1 mL (except in bilateral vasal agenesis or hypogonadism)
• Suspicion of retrograde ejaculation 1

Specialized Testing

Genetic Testing

Indicated for:

• Men with nonobstructive azoospermia
• Men with severe oligospermia (<5-10 million sperm/mL)
• Men with congenital bilateral absence of vas deferens

Types of genetic tests:

• Karyotyping
• Y-chromosome microdeletion analysis
• Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation testing (for female partners of men with congenital bilateral absence of vas deferens) 1

Sperm DNA Fragmentation Testing

Consider in cases of:

• Failed assisted reproductive technology cycles
• Recurrent pregnancy losses (two or more) 1

Imaging Studies

Scrotal Ultrasonography

Indicated when:

• Physical examination of scrotum is difficult or inadequate
• Testicular mass is suspected 1

Transrectal Ultrasonography (TRUS) or Pelvic MRI

May be recommended for:

• Men with suspected ejaculatory duct obstruction
  • Acidic, azoospermic semen with volume <1.4 mL
  • Normal serum testosterone
  • Palpable vas deferens 1

Common Pitfalls and Caveats

1. Single semen analysis can be misleading: Parameters fluctuate substantially; at least two analyses are recommended 1

2. WHO reference limits are based on the lowest 5th percentile of values from fertile males whose partners became pregnant within 12 months 1

3. Routine use of ultrasonography for non-palpable varicoceles should be discouraged as treatment of non-palpable varicoceles does not improve fertility rates 1

4. Specialized testing of semen (beyond basic analysis) is not required for diagnosis of male infertility but may be useful in select cases 1

5. Interpreting FSH levels: Men with FSH >7.6 IU/L are more likely to have spermatogenic failure (non-obstructive azoospermia) 1, 2

By following this systematic approach to laboratory testing for male fertility, clinicians can effectively identify potential causes of infertility and guide appropriate treatment decisions.