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Also known as: total PSA; free PSA; complex PSA
Formal name: Prostate-Specific Antigen
Related tests: Rectal examination

At a Glance

Why Get Tested?

To help detect and to monitor prostate cancer

When to Get Tested?

If you have symptoms of prostate disease, such as difficulty in passing urine, or passing urine more frequently than usual

Sample Required?

A blood sample taken from a vein in the arm

The Test Sample

What is being tested?

Blood is being tested for the level of PSA it contains. PSA is a protein produced mainly by cells in the prostate gland and can be a useful indicator of prostate cancer. This protein can be found in all males; however, men whose levels are increased may have an infection of the prostate gland (prostatitis), prostate enlargement or prostate cancer. In blood, PSA is present both as free PSA and as complexed PSA bound to other blood proteins. The free PSA test measures the percentage of the total PSA that is not bound to proteins in the patient’s blood.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm. You are likely to be advised to avoid ejaculation and vigorous physical activity affecting the prostate, such as bicycle riding, during the two days before the blood test. A blood sample should not be taken until at least a week after a digital rectal examination.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

The Test

Common Questions

Ask a Laboratory Scientist

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.