PSA (total)

UK guidance uses age-related thresholds: 3.0 ug/L below 70 and 5.0 from 70. Many labs print 4.0 or an age band.

PSA, prostate specific antigen, is a protein made by the prostate gland and found in small amounts in the blood of all men. The amount rises as the gland enlarges with age and with many benign conditions. Tumour markers are proteins that can rise for many reasons, most of them not cancer. Specialists mainly use them to follow a condition that has already been identified, and a single value cannot answer a screening question on its own.

GPs test it in men with urinary symptoms, in men who ask for it after a discussion of the pros and cons, and specialists use it to follow the prostate over time.

• Increasing age and a larger prostate
• Prostate inflammation or a urine infection
• Ejaculation in the previous 48 hours
• Vigorous cycling or a rectal examination shortly before the test
• Urinary retention or a catheter
• Prostate cancer

• Some prostate medicines as a class roughly halve it
• Being overweight lowers it slightly

• The age-related thresholds UK GPs use are 3.0 up to age 69 and 5.0 from 70
• Any single value can be raised by infection, exercise or recent ejaculation, so a repeat after six weeks is common
• Values drift slightly between methods

Avoid ejaculation and vigorous exercise for 48 hours, and any urine infection should be treated and cleared first. The trend over years is more informative than one value.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.