Reasoning GP · Algorithm · 1-page summary
Abnormal semen analysis in primary care
For: men with an abnormal semen analysis, as part of a couple's fertility assessment. Not for: acute testicular pain or a lump alone (testicular pain / lump algorithms); partner's work-up (infertility protocol).
Core rule: one abnormal result is not a diagnosis — repeat it, examine the testes, investigate both partners in parallel; but azoospermia or a testicular lump never waits for the repeat, and never start testosterone in a man trying to conceive.
0Act now — before interpreting any count
- Sudden severe testicular pain, pain with vomiting or abdominal pain, or suspected torsion → 999 or A&E immediately; do not drive.
- Unexplained intratesticular mass, or non-painful enlargement or change in shape or texture (any age) → consider Suspected cancer urology referral (NG12) and urgent direct-access ultrasound; do not wait for tumour markers or the repeat sample.
1Triage the result — WHO 2021 lower reference limits
| Parameter | Reference · below it |
|---|---|
| Concentration | ≥16 million/mL; total ≥39 million → oligozoospermia |
| Motility | Progressive ≥30%; total ≥42% → asthenozoospermia |
| Morphology | ≥4% normal forms → teratozoospermia |
| Volume · pH | ≥1.4 mL · ≥7.2; low: obstruction, retrograde, lost sample |
| No sperm | Azoospermia → repeat soon and refer now (block 2) |
5th centiles, not fertility cut-offs. Abnormal → repeat ideally at 3 months (as soon as possible if azoospermia or severe oligozoospermia).
2Screen — prompt andrology / reproductive medicine
- Azoospermia, <1 million/mL, or prior chemo- / radiotherapy needing urgent fertility preservation → Prompt; do not wait for the repeat.
- Absent vas (CBAVD) → andrology + CFTR testing; partner testing, counselling via genetics / fertility.
- Small testes + raised FSH, or Klinefelter features (gynaecomastia, tall) → andrology / genetics; karyotype; no testosterone.
- Low testosterone with low or normal LH/FSH, galactorrhoea, headache or visual symptoms → prolactin; pituitary failure → Prompt endocrine / andrology.
- Varicocele: sudden, non-reducible, isolated right-sided or not decompressing supine → scrotal + renal / retroperitoneal ultrasound; discuss with urology.
3Assess
☐ Cryptorchidism, torsion, mumps, epididymo-orchitis, surgery, chemotherapy, CF family history, sexual symptoms ☐ Ask directly: anabolic steroids, testosterone, sulfasalazine, cannabis, alcohol, heat ☐ After two abnormal analyses (sooner if indicated): examine testes, epididymides, vasa, varicocele (standing, Valsalva), sexual characteristics ☐ Consider morning testosterone + LH/FSH (repeat testosterone if low) ☐ Idiopathic azoospermia: karyotype + Y microdeletion (Y also if <1 million/mL; consider karyotype if persistent <5 million/mL); CFTR if suspected obstruction or vasal abnormality
Not in primary care: sperm DNA fragmentation, routine scrotal ultrasound or cortisol, karyotype for mild isolated abnormality, MRI for mildly raised prolactin.
4Classify — only if blocks 0–2 are negative
- Hypogonadotrophic — low FSH, LH and testosterone: Kallmann (anosmia), prolactinoma, anabolic steroids, obesity → specialist gonadotrophin therapy, not testosterone.
- Testicular — raised FSH, small testes: Klinefelter, cryptorchidism, chemotherapy → andrology.
- Obstructive — normal FSH and testes (suggestive, not proof): CBAVD, post-infective, ejaculatory duct (low volume / pH) → andrology.
- Retrograde ejaculation — diabetes, pelvic surgery, tamsulosin → post-ejaculatory urine.
- Mild, borderline abnormality — lifestyle, medicine review, repeat in 3 months; normal → reassure; abnormal → refer.
- Uncertain — say so; refer the couple.
5Treat today — only these
- Stop anabolic steroids and exogenous testosterone if fertility is desired; review sulfasalazine and other culprit medicines.
- Lifestyle: stop smoking (NHS Stop Smoking Service), cannabis, recreational drugs; alcohol within 14 units/week; weight if BMI ≥30; avoid excessive scrotal heat (evidence limited).
- No supplements as standard treatment; folic acid for the person who may become pregnant, not routinely for men. Clomifene or gonadotrophins for idiopathic impaired semen: only in a clinical trial; no androgens.
- Support both partners (Relate, Fertility Network UK).
6Refer routinely
- Abnormal result confirmed on repeat → refer the couple to reproductive medicine; no further 6–12 months' wait.
- At presentation if the person trying to conceive is 36 or over, or either partner has a known or predisposing cause; otherwise after 12 months of regular unprotected intercourse.
- Palpable varicocele + abnormal semen analysis, no better explanation → specialist to consider treatment; not subclinical ones; promise nothing.
- Karyotype abnormality, Y microdeletion, CFTR variant or CBAVD → clinical genetics; counselling before assisted conception. NHS IVF access follows the local ICB policy.
7Never reassure by
- A value above the reference limit — it does not guarantee fertility.
- Normal tumour markers when there is a testicular lump.
- Waiting for the repeat, or a further year, before referring azoospermia.
- Treating low testosterone with testosterone in a man trying to conceive.
- A history without a direct question about anabolic steroids.
- Investigating one partner first — both run in parallel.
8Safety-net — say it, then document it
999 “Sudden severe pain in a testicle, or pain with vomiting or tummy pain: call 999 or go to A&E now — don't drive yourself.” Urgent “A new lump, swelling, or change in the shape or feel of a testicle: book an urgent GP appointment or call 111 — don't wait for the fertility review.” Review: book the repeat sample; agree who reviews the result and when.
✓Safe to leave primary care only if — all five, documented
No block 0–2 row applies; testes examined
Result repeated, or repeat booked with correct collection
Steroid, testosterone and medicine history taken
Partner investigated in parallel; referral checked
Safety-net given and documented
Summary of the full Reasoning GP abnormal semen analysis algorithm, which holds causes, genetics, assisted conception and evidence. Sources: NICE NG257 (March 2026, replaced CG156), WHO Laboratory Manual 6th edition 2021, NICE NG12 (updated April 2026), EAU Sexual and Reproductive Health 2026, British Andrology Society; local fertility commissioning policy. Clinical reference — follow local pathways.