What laboratory tests are used to assess male fertility?

Laboratory Tests for Male Fertility Assessment

The initial evaluation for male fertility assessment should include a comprehensive reproductive history, physical examination by a trained examiner, and at least one properly performed semen analysis, with additional endocrine testing when indicated by abnormal findings. 1, 2

Core Laboratory Tests

1. Semen Analysis (First-Line Test)

• At least two semen analyses should be performed at least one month apart 1, 2
• Collection parameters:
  • 2-3 days of sexual abstinence before collection
  • Collection by masturbation or using special non-toxic condoms
  • Specimen kept at body temperature during transport
  • Examination within one hour of collection 1
• Standard parameters assessed:
  • Volume: 1.5-5.0 mL
  • pH: >7.2
  • Sperm concentration: >20 million/mL
  • Total sperm count: >40 million per ejaculate
  • Motility: >50%
  • Forward progression: >2 (on scale of 0-4)
  • Morphology: varies between WHO and Kruger criteria 1

2. Endocrine Evaluation (Second-Line Test)

• Indications:
  • Abnormal semen parameters (especially concentration <10 million/mL)
  • Impaired sexual function
  • Clinical findings suggesting endocrinopathy 1
• Minimum testing:
  • Serum testosterone
  • Follicle-stimulating hormone (FSH) 1
  • Additional hormones as indicated (LH, prolactin, thyroid function)

Specialized Tests (When Indicated)

1. Post-Ejaculatory Urinalysis

• Indications: Ejaculate volume <1 mL (except in bilateral vasal agenesis or hypogonadism)
• Purpose: Evaluate for retrograde ejaculation 1

2. Imaging Studies

• Transrectal ultrasound (TRUS):
  • For azoospermic men with palpable vasa and low ejaculate volumes
  • To evaluate for ejaculatory duct obstruction 1
• Scrotal ultrasound:
  • When physical examination is difficult or inadequate
  • When testicular mass is suspected 1

3. Advanced Sperm Function Tests

• Not required for routine diagnosis but may be useful in select cases:
  • Sperm DNA fragmentation tests
  • Oxidative stress assessment
  • Specialized tests for unexplained infertility or to guide assisted reproduction 3

Diagnostic Algorithm

1. Initial Screening:

   • Reproductive history
   • Physical examination
   • Two semen analyses

2. If semen analysis is abnormal:

   • Endocrine evaluation (testosterone, FSH)
   • Additional tests based on specific abnormalities:
     • Low volume: Post-ejaculatory urinalysis
     • Azoospermia with palpable vasa: TRUS
     • Difficult scrotal exam: Scrotal ultrasound

3. If initial screening is normal but infertility persists:

   • Consider specialized sperm function tests
   • Evaluate female partner (if not already done)

Important Clinical Considerations

• Multiple parameters are superior: Assessment of multiple semen parameters together provides better prediction of fertility than any single parameter alone 1
• Variability in results: Semen parameters can vary significantly between samples, highlighting the importance of at least two analyses 1
• Laboratory quality: Adherence to standardized WHO methods is critical for accurate results, as poor laboratory technique is a major source of variability 1
• Substantial overlap: There is considerable overlap in semen parameters between fertile and infertile men, making interpretation challenging 1

Common Pitfalls to Avoid

• Relying on a single semen analysis
• Focusing solely on sperm count while ignoring other parameters
• Failing to perform endocrine testing when indicated
• Not considering the male partner in infertility evaluations
• Using non-standardized laboratory techniques
• Overlooking the importance of proper specimen collection and handling

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