The sperm sample: what the lab does with it and what the report means

Half of embryology is about sperm, and the semen report is often the first piece of paper a couple sees. Here is what the lab does with a sample and how to read the report without panic.

What the lab measures

• Volume — normally 1.5 ml or more.
• Concentration — millions per ml. WHO reference (2021): about 16 million/ml or more. Total count (concentration × volume) matters more than concentration alone.
• Motility — the share of sperm that are moving, and how well. "Progressive" motility (moving forward) is what counts for reaching an egg; reference around 30% progressive, 42% total.
• Morphology — the share with a "normal" shape under strict criteria; reference around 4%. Yes, four. Most sperm in most men look abnormal by this standard, which is why morphology alone is rarely decisive.
• Vitality — share alive (relevant when motility is very low).
• Other findings — clumping, round cells (may suggest infection or immature cells), pH.

The report compares your numbers with the WHO reference ranges. "Below reference" is a flag for the doctor to weigh with everything else, not a diagnosis by itself. Results vary a lot from sample to sample — illness, fever, stress, abstinence time and even season change them — so a single poor result is usually repeated before conclusions are drawn.

Beyond the routine report

• DNA fragmentation (DFI) — measures breaks in the sperm's genetic material. High DFI (thresholds vary, often quoted around 25–30%) has been linked to lower fertilisation, poorer embryo development and miscarriage. Not routine everywhere; useful in recurrent failure or unexplained cases. Lifestyle changes and shorter abstinence can lower it.
• Antisperm antibodies, culture for infection, and hormonal or genetic tests are ordered by the doctor when the picture suggests them.

Sperm preparation ("washing")

On the day of egg collection or insemination, the sample is prepared: seminal fluid, dead sperm, debris and round cells are separated from the good swimmers, usually by layering the sample over a density gradient and spinning it, or by letting motile sperm swim up into clean medium. What's left is a small volume of concentrated, motile sperm ready for IVF, ICSI or intrauterine insemination.

When the numbers are very low or zero

• Very low counts — ICSI needs only one healthy sperm per egg, so pregnancies are routine even with a handful of moving sperm.
• No sperm in the ejaculate (azoospermia) — sperm can often be retrieved directly from the testis or epididymis by a small procedure (TESA/TESE/micro-TESE) and used for ICSI. This is a specialist area and worth a dedicated conversation.
• Freezing a back-up sample before egg collection is common when the result has been variable, so the day isn't at the mercy of one sample.