PSA blood test for prostate cancer

The test uses a blood sample to measure prostate-specific antigen, a substance released by prostate tissue. The result may be affected by cancer, benign enlargement, inflammation, infection, ejaculation, or recent prostate manipulation. This is why the number is interpreted with the person’s symptoms and medical history rather than in isolation.

A clinician may compare the result with earlier tests and consider how quickly it changed. An unexpected result may lead to a repeat sample or another examination. Information about [Prostate Cancer](/conditions/prostate-cancer/) can help explain the wider diagnostic pathway.

Before testing or retesting, tell the clinician about urinary infection, fever, catheterisation, prostate procedures, and medicines for urinary symptoms. Mention new [Difficulty Passing Urine](/symptoms/difficulty-passing-urine/) rather than waiting for the blood result to explain it.

Keep a record of the date and reason for each PSA test. If the result needs clarification, ask whether a repeat test, prostate examination, MRI, or biopsy is appropriate. Decisions should reflect the whole clinical picture and your preferences.

Contact a clinician about an abnormal or rising result and report urinary changes, blood in urine or semen, or persistent pain in the pelvis, back, or hips. Seek urgent help if urine will not pass, or if urinary symptoms occur with fever, chills, or marked illness.

Ask why the blood test was requested, what non-cancer causes could affect it, and whether any preparation or timing matters for a repeat. Ask what further information would be gained from MRI or biopsy before choosing a next step.