How to Read a Semen Analysis: What Every Number Means
Explains each semen analysis number using WHO 2021 reference values. For anyone reviewing a lab report and wanting to understand what the results mean.
A semen analysis comes back with six to eight numbers, and most people focus on one of them and panic. Understanding what each parameter measures — and how to read them together — gives a more accurate picture than any single result in isolation. Here's what the report is actually telling you.
What does a semen analysis test for?
A standard semen analysis measures several parameters at once: volume, concentration, total sperm count, progressive motility, total motility, morphology, vitality, pH, and white blood cell count. Not every lab reports all of these, and some may only appear if ordered specifically. The report uses WHO 2021 reference values as the lower limit of normal — meaning 5% of fertile men fall below each threshold. Below reference does not mean infertile; the full picture matters more than any single line.
What is a normal sperm count?
The WHO 2021 reference values set sperm concentration at ≥15 million per mL, with a total sperm count of ≥39 million per ejaculate (volume multiplied by concentration). Volume should be at least 1.4 mL; low volume can indicate a collection issue, retrograde ejaculation, or a ductal problem. These thresholds represent the lower limit observed in fertile men — not a minimum required for conception.
What does sperm morphology mean and what percentage is considered normal?
Morphology refers to sperm shape — specifically, what proportion of sperm look structurally typical under Kruger strict criteria. The reference value is ≥4% normal forms. This number surprises most people: "4% normal" sounds alarming, but it reflects Kruger strict analysis, which is a highly specific grading system. A result below 4% does not rule out pregnancy; it shifts the clinical picture but is not a standalone diagnosis of infertility.
What does sperm motility mean and what is a passing result?
Motility measures movement. Progressive motility — sperm moving forward in a directed, useful way — should be ≥30%. Total motility, which includes any movement at all, should be ≥42%. Vitality (the percent of sperm that are alive) carries a reference of ≥54%. Motility is often more predictive of fertility potential than count alone, which is why a report with a high count but low motility still warrants careful attention.
What does it mean if a semen analysis is abnormal?
A single parameter slightly below reference is usually not concerning on its own. Context matters: a mildly low concentration in an otherwise normal report is a different situation from multiple parameters below reference, or one severely low result — such as concentration under 5 million per mL. That kind of finding changes the clinical picture and warrants referral to urology or andrology for further evaluation rather than simple watchful waiting.
What is total motile sperm count and why does it matter for IUI?
<!-- H2 references IUI specifically; source deck does not address IUI by name. Answered using source content on motility parameters and motility's predictive role. --> Total motile sperm count reflects how many sperm in a sample are actively moving forward — it draws on volume, concentration, and progressive motility together. The SA parameters that feed into this picture are progressive motility (≥30%) and total motility (≥42%). Because motility is often more predictive of fertility than count alone, these values together give a more complete view of a sample's reproductive potential than any single number by itself.
Can semen analysis results change over time?
Yes — semen quality fluctuates. Illness in the two to three months before the test, fever, significant stress, heat exposure, and ejaculation frequency can all affect the results. For this reason, one abnormal semen analysis is not a diagnosis. The clinical standard is to repeat the test two to three weeks to three months after the first result, especially if any parameter was significantly below reference.