Semen pH
Fertility marker
Semen pH
Acidity of the ejaculate. Reflects the balance between the alkaline seminal vesicle fluid and the acidic prostatic secretion.
PED Notes
Rarely abnormal and rarely acted on in isolation, but it becomes genuinely useful in one specific situation: a low volume, acidic, sperm-free sample points toward obstruction or absence of the vas deferens or seminal vesicles rather than a production problem. That distinction matters because it separates a plumbing issue from a spermatogenesis issue, and the two have completely different management. Alkaline pH above about 8 is more often infection or inflammation. On its own an odd pH means little; read it with volume and count.
When high
Alkaline semen most often accompanies infection or inflammation of the accessory glands.
- Check for raised leukocytes on the same report and consider a semen culture if there are symptoms.
- Persistent inflammation raises oxidative stress, so check Sperm DNA Fragmentation if you are trying to conceive.
- A mildly high pH with everything else normal is generally not acted on.
When low
Acidic semen matters most when it appears with low volume and absent or very low sperm count. That combination suggests the alkaline seminal vesicle contribution is missing, which points toward obstruction or congenital absence of the vas deferens rather than failed sperm production.
If volume is low and pH is acidic:
- This warrants a urologist rather than a supplement plan. Investigation usually includes a scrotal and transrectal ultrasound, and CFTR genetic testing, since congenital bilateral absence of the vas deferens is associated with cystic fibrosis mutations.
- Read alongside Semen Volume and Sperm Concentration.
If volume and count are normal, a slightly low pH on its own is not clinically meaningful.
Collection artefact: an incomplete sample, or one analysed hours after production, can shift pH. If the sample was partial or delayed, repeat before drawing conclusions.
History Chart
Reading History
Frequently Asked Questions
Reference Ranges
Standard Range