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PSA Test (Prostate-specific Antigen): Why and How is it Done?

PSA Test (Prostate-specific Antigen): Why and How is it Done?

The PSA test or Prostate-Specific Antigen blood test analyzes the level of prostate-specific antigen in the bloodstream of males. PSA is a protein produced by the prostate, a small gland that sits below the bladder in men.

Prostate-specific antigen levels generally rise with age. PSA levels over the normal range might be an indicator of the signs of prostate cancer. Although, it does not confirm the prevalence of cancerous growth. This is because higher PSA levels may be a sign of other non-cancerous medical conditions. These disorders include enlargement of the organ amongst the elderly, benign prostatic hyperplasia (BPH), urinary infection, inflammatory condition of prostatitis, etc.


Since this PSA blood test does not confirm the presence of cancer in the prostate, doctors often recommend other prostate tests along with this test for accurate diagnosis.

Why is the Protein Specific Antigen Test done?

The PSA blood test screens for the presence of unbound PSA. More specifically, the test is advised in the following instances:

  • Men who have successfully undergone treatment for prostate cancer may be recommended this test to detect the signs of recurrence of the condition.
  • It can be advised for monitoring the growth or shrinking of the cancerous growth after treatment with radiation or hormones.
  • It may also be recommended to diagnose early-stage prostate cancer, even before there are external manifestations of symptoms.

Prerequisites of the Protein Specific Antigen Test

Ejaculation has to be avoided for 24 to 48 hours before undergoing the PSA blood test. Hence, you have to abstain from sexual activities during this span of time. This is because ejaculation may raise PSA levels.

It is essential for you to discuss the medications and lab tests that you may be taking now or have taken in the recent past with your doctor. In case you have undergone a needle biopsy or cystoscopy of the prostate, discuss this with your doctor. So they can best decide how to proceed.

Let your doctor know about the medications that you might be taking. Such medications include prescription drugs, non-prescription or OTC (over-the-counter) drugs, vitamins, supplements, and herbals.

Make sure to carry your medical documents for the doctor to thoroughly check the prescription drugs that you might be taking now. This will enable them to analyze whether any of these medications have a known history of interfering with outcomes of this blood test. They will then be able to advise you accordingly.

Understanding the Results

A specific normal value for PSA is hard to determine, as it varies in the same individual from time to time. For patients between the ages of 50 and 69 years, PSA levels of 4 ng/ml or less is considered to be normal.

As mentioned, elevated levels of PSA may be a sign of prostate cancer and other medical conditions like prostatitis, benign enlargement of the organ, etc.

Early-stage prostate cancers that are diagnosed through this test are usually localized in nature. Such conditions usually do not affect the quality of life or longevity of patients.

When should this test be repeated?

There is a high risk of the PSA blood test generating a false negative result. This implies that the test result might be normal despite the presence of prostate cancer.

If the doctor suspects this, they might recommend a repeat PSA test. Possibly along with other tests to confirm the result. Other medical tests that may be advised are imaging tests like X-rays, transrectal ultrasound, and/or cystoscopy.

In cases where patients with no symptoms of cancer in the prostate decide to undertake a PSA blood test, the doctor may advise them to undertake the test again. This will help in confirming the accuracy of the test results.

Protein Specific Antigen Test: Procedure

The PSA blood test involves a medical expert collecting blood from a patient as a sample for analysis at a laboratory. The healthcare professional selects a suitable vein, usually from the inner corner of the elbows or the hands.

  • The expert applies an antiseptic solution to clean and numb the area and then wraps an elastic band around the arm. This serves the purpose of making the vein swell and more visible from the skin’s surface. It improves the chances of injecting the needle accurately.
  • Next, the needle is injected to draw blood, which gets collected in the vial of the injection. The bleeding from the puncture site is prevented with a clean cotton swab.
  • Then the wound is covered with a bandage. The bandage accelerates the healing process and keeps infections away. This bandage can be disposed of after 10 to 15 minutes. Unless advised differently by your healthcare professional.

The entire procedure does not generally extend beyond a few minutes. The pain differs between patients, varying from a mild prick to a sharp sting. Finally, the blood sample is sent to a laboratory for microscopic evaluation.

Learn more about cancer diagnosis and management here.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Prostate Specific Antigen-Free (Free PSA) https://www.nightingales.in/lab-tests/tests/prostate-specific-antigen-free-free-psa/55c0e27e02c54d0c001bf115 Accessed on 23/07/2020

Prostate-Specific Antigen (PSA) Test https://www.cancer.gov/types/prostate/psa-fact-sheet Accessed on 23/07/2020

Prostate cancer screening https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5494343/ Accessed on 23/07/2020

PSA testing https://www.nhs.uk/conditions/prostate-cancer/psa-testing/ Accessed on 23/07/2020

Should I have a PSA test? https://www.nhs.uk/conditions/prostate-cancer/should-i-have-psa-test/ Accessed on 23/07/2020

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Written by Nikita Bhalla Updated Sep 29, 2021
Fact Checked by Bianchi Mendoza, R.N.