What does a semen analysis result of less than 0% motile sperm concentration indicate?

Understanding <0% Motile Sperm Concentration

A semen analysis result showing <0% (or 0%) motile sperm concentration means that no moving sperm were detected in the fresh, uncentrifuged sample—but this does NOT necessarily mean the patient is azoospermic or completely infertile.

What This Result Actually Indicates

• The finding represents complete asthenozoospermia (absence of motile sperm), but sperm may still be present in the ejaculate—they are simply non-motile. 1

• This is fundamentally different from azoospermia, where no sperm are present at all. The distinction is critical because non-motile sperm can potentially be used for assisted reproductive technology (ART) with intracytoplasmic sperm injection (ICSI). 2

Critical Next Step: Centrifugation Analysis

You must perform semen centrifugation (sperm pellet analysis) before concluding anything about fertility potential. 2

• After centrifugation, motile or non-motile sperm are identified in approximately 20-23% of men initially thought to have azoospermia by routine analysis. 2

• Motile sperm were found in the pellets of 21.4% of men with non-obstructive azoospermia and 8.6% of men with obstructive azoospermia after centrifugation. 2

• The median number of motile sperm after centrifugation was 5 sperm in non-obstructive cases, demonstrating that even "0% motility" on routine analysis doesn't preclude finding usable sperm. 2

Clinical Context Matters: Timing and Technique

Sample Handling Requirements

• The specimen must be examined within 2 hours of ejaculation to accurately assess motility, as sperm viability decreases over time. 1

• The sample should be fresh, uncentrifuged, and well-mixed for the initial motility assessment. 1

• WHO guidelines recommend analysis within 60 minutes when collected in the laboratory, but 2 hours is acceptable for post-vasectomy analysis where only presence/absence of motility matters. 1

Post-Vasectomy Context

If this result is from post-vasectomy semen analysis (PVSA):

• Patients may stop using contraception when PVSA shows only rare non-motile sperm (RNMS, defined as <100,000 non-motile sperm/mL). 1

• The risk of pregnancy with RNMS is very low and similar to complete azoospermia (approximately 1 in 2,000). 1

• Any motile sperm at 6 months post-vasectomy indicates vasectomy failure and warrants consideration of repeat vasectomy. 1

Differential Diagnosis Algorithm

If NOT Post-Vasectomy, Consider:

Obstructive Causes:

• Ejaculatory duct obstruction typically presents with low volume (<1.4 mL), acidic pH (<7.0), and absent or very low motility. 1

• Failed vasectomy reversal, congenital vasal/epididymal occlusion, or acquired obstruction. 2

• Congenital bilateral absence of vas deferens (CBAVD). 1

Non-Obstructive Causes:

• Primary testicular failure with testicular atrophy and elevated FSH (>7.6 IU/L). 1, 3

• Klinefelter syndrome or other chromosomal abnormalities. 1, 3

• Y-chromosome microdeletions (AZFa, AZFb, AZFc regions). 1, 3

• Maturation arrest or Sertoli-cell-only syndrome. 2

Reversible/Iatrogenic Causes:

• Exogenous testosterone or anabolic steroid use (completely suppresses spermatogenesis). 3

• Recent illness, fever, or heat exposure affecting sperm motility. 4

• Improper sample collection or prolonged time to analysis (>2 hours). 1

Essential Diagnostic Workup

Immediate Steps:

1. Repeat semen analysis with centrifugation after 2-3 days abstinence, analyzed within 1-2 hours. 4, 2

2. Obtain at least two semen analyses separated by 2-3 months due to significant intra-individual variability. 4

3. Measure serum FSH, LH, and total testosterone to distinguish obstructive from non-obstructive causes. 1, 3

If Centrifuged Sample Shows Sperm <5 Million/mL:

• Perform karyotype analysis to screen for Klinefelter syndrome (47,XXY) and other chromosomal abnormalities. 1, 3

• Obtain Y-chromosome microdeletion testing (AZFa, AZFb, AZFc regions), as deletions occur in 5% of men with concentrations 0-1 million/mL. 1, 3

Physical Examination Priorities:

• Assess testicular volume (normal ≥12 mL; <12 mL suggests atrophy). 5

• Palpate for varicocele on standing examination. 1, 3

• Confirm presence and consistency of vas deferens bilaterally. 1

• Check for epididymal abnormalities or induration. 1

Fertility Prognosis and Treatment Options

If Non-Motile Sperm Are Present After Centrifugation:

• ICSI with ejaculated non-motile sperm is possible and represents the first-line approach before considering testicular sperm extraction. 2

• Even completely non-motile sperm can achieve fertilization rates of 50-60% with ICSI if DNA integrity is preserved. 2

If True Azoospermia Is Confirmed:

• Microsurgical testicular sperm extraction (micro-TESE) achieves 40-60% sperm retrieval rates in non-obstructive azoospermia, even with elevated FSH. 3

• Micro-TESE is 1.5 times more successful than conventional TESE and causes less testosterone suppression. 3

• Complete AZFa or AZFb deletions predict near-zero retrieval success and contraindicate TESE. 3

Critical Pitfalls to Avoid

• Never diagnose azoospermia without centrifugation analysis, as 20-23% of "azoospermic" men have sperm in the pellet. 2

• Never start testosterone replacement if fertility is desired, as it will cause complete azoospermia that may take months to years to recover. 3

• Do not rely on a single semen analysis due to significant biological variability—always obtain at least two samples 2-3 months apart. 4

• Avoid assuming "0% motility" means no fertility potential—non-motile sperm can be successfully used for ICSI. 2

• Do not delay sperm cryopreservation if testicular failure is suspected, as parameters may deteriorate further. 3