👤 Reading Your Sperm Analysis Report: WHO 2021 Criteria Explained

A semen analysis (SA) is the foundational test for evaluating male fertility. It is inexpensive, fast, and provides more information than any single test on the female side. Yet most reports are handed back with cryptic numbers and a confusing reference range, leaving patients to wonder whether "low normal" actually means anything.

This guide walks through the WHO 2021 (sixth edition) reference values — the global standard — and explains what each parameter measures and what abnormal results mean in practice.

How the Sample Is Collected and Analyzed

The sample is typically produced by masturbation at the lab or at home (collected into a sterile container and delivered to the lab within 60 minutes, kept at body temperature). You will be asked to abstain from ejaculation for 2 to 7 days before the test. Same-day intercourse before the sample distorts results.

The lab analyzes the sample under microscope within 30 to 60 minutes of production. Computer-assisted sperm analysis (CASA) is used in many modern labs alongside manual assessment.

The WHO 2021 Reference Values

These are the 5th centile values — meaning 95 percent of recently fertile men exceed these numbers. Below these is considered subfertile but does not mean infertile.

Volume: 1.4 mL or more

The total fluid volume of the ejaculate. Very low volume may indicate retrograde ejaculation (where semen goes backward into the bladder), partial blockage, or hormonal issues.

pH: 7.2 or higher

Normal semen is slightly alkaline. Abnormal pH may suggest infection or duct obstruction.

Sperm concentration: 16 million per mL or more

The number of sperm per milliliter. Below 16 million/mL is oligozoospermia (low concentration).

Total sperm number: 39 million or more per ejaculate

Volume multiplied by concentration. This is arguably more clinically relevant than concentration alone.

Total motility: 42 percent or more

The percentage of sperm that are moving, including both progressive and non-progressive motion.

Progressive motility: 30 percent or more

The percentage of sperm moving forward in a relatively straight line. This is the most clinically important motility measure. Reduced progressive motility is called asthenozoospermia.

Morphology (normal forms): 4 percent or more

The percentage of sperm with normal shape, evaluated by strict Kruger criteria. Yes, 4 percent is genuinely normal — most sperm in any sample have minor abnormalities. Below 4 percent is teratozoospermia.

Vitality (live sperm): 54 percent or more

The percentage of live sperm, important especially when motility is very low.

What the Diagnostic Labels Mean

Reports often include one or more of these terms:

• Normozoospermia: all parameters meet or exceed WHO reference values
• Oligozoospermia: low sperm concentration or total count
• Asthenozoospermia: low motility
• Teratozoospermia: low normal morphology
• Oligoasthenoteratozoospermia (OAT): all three reduced
• Azoospermia: no sperm in the ejaculate (requires further evaluation — could be obstructive or non-obstructive)
• Cryptozoospermia: sperm only found after centrifugation

Why One Bad Result Should Not Panic You

Sperm production cycles take roughly 72 days. A single SA reflects sperm produced over the preceding 2 to 3 months. Recent illness with fever, viral infection (including COVID-19), heat exposure (hot tubs, fever, occupational heat), heavy alcohol use, certain medications, and stress can all temporarily depress sperm parameters.

ASRM recommends at least two semen analyses spaced 2 to 3 months apart before drawing firm conclusions, particularly if the first result is abnormal.

What Abnormal Results May Trigger

Depending on the pattern, follow-up may include:

• Repeat semen analysis at 2 to 3 month intervals
• Hormonal blood panel: FSH, LH, testosterone, prolactin, sometimes TSH and estradiol
• Genetic testing: karyotype, Y-chromosome microdeletion analysis, CFTR mutation (cystic fibrosis carrier status) screening, especially for severe oligozoospermia or azoospermia
• Scrotal ultrasound: to look for varicocele (enlarged scrotal veins) or other structural issues
• Urology referral: a reproductive urologist is the equivalent of an RE for the male partner
• Sperm DNA fragmentation testing (SCSA or similar): in selected cases of recurrent pregnancy loss or failed IVF

How Severe Is the Abnormality?

A helpful frame:

• Mild abnormality: still typically compatible with natural conception or IUI
• Moderate abnormality: often requires IUI or IVF
• Severe abnormality (very low count, very low motility): typically requires IVF with ICSI
• Azoospermia: requires surgical sperm retrieval (TESE/TESA/MESA) plus IVF/ICSI

Lifestyle Factors That Genuinely Affect Sperm

• Heat: avoid hot tubs, saunas, laptops on the lap, and tight underwear
• Smoking and cannabis: both have well-documented adverse effects
• Alcohol: heavy use lowers sperm quality
• Anabolic steroids and testosterone therapy: suppress sperm production, sometimes permanently
• Obesity: associated with lower sperm quality
• Certain medications: discuss with your physician

Talking to Your Doctor

Reasonable questions:

• Which parameters are abnormal and by how much?
• Should we repeat the test?
• Do I need a urology referral?
• Are there lifestyle changes likely to help in my specific case?
• What treatment options does this result point toward?

Confirm interpretation and next steps with your reproductive endocrinologist or reproductive urologist. To find male fertility specialists near you, use the Fertility Link Navigator.