Things Impacting PSA Test Results

Updated July 18, 2017

The PSA test is important in monitoring men's health and is the first step in the diagnosis of prostate cancer. Prostate-specific antigen, or PSA, is present in every man's blood in small amounts. This normal, low level of PSA is known as the baseline and is referred to when PSA rises or falls. An increase in PSA can mean irregular functioning of the prostate gland because of benign prostatic hyperplasia, or BPH; inflammation; infection; or prostate cancer. PSA testing is far from definitive in the detection of a prostrate problem; because many factors can affect the test results.

Benign Prostatic Hyperplasia

Benign prostatic hyperplasia is the benign enlargement of the prostate gland. BPH is frequently the cause of frequent nighttime urination, urinary retention, difficulty voiding and urinary infections. BPH causes an increase in PSA levels.


The inflammation or infection of the prostate also causes elevated PSA levels. PSA testing should be done after any infection has cleared and after inflammation has subsided, if possible.


Age also causes a change in PSA levels. In general, the older the patient, the higher the level. This complicates the detection of prostate cancer, because the normal ranges for PSA cannot be adjusted to reflect age-related changes without the risk of possibly not detecting cancer.


Ejaculation through sexual intercourse or masturbation causes PSA levels to rise for 24 to 48 hours. If you are having a PSA test, it is recommended that you abstain from ejaculation for at least two days before to the test.

Medications and Herbal Supplements

Various medications and herbal supplements can affect PSA results. in particular might lower results and mask true increases in PSA. Drugs such as finasteride (Proscar/Propecia) and dutasteride (Avodart), which are commonly prescribed for BPH and baldness, can lower PSA results by up to 50 per cent. Non-steroidal anti-inflammatory drugs (including aspirin and ibuprofen), and herbal dietary supplements for prostate health, can also falsely lower PSA levels.


Obesity presents a challenge for measuring PSA results, because patients who are obese have lower PSA levels. These inaccurate results and make prostate problems difficult to diagnosis. Many obese patients can be accurately diagnosed only after prostate cancer has spread to another area of the body.

Injury and Vigorous Exercise

Injury to the prostate area can affect PSA levels. Inform your physician if you have been injured before PSA testing. Vigorous exercise, such as cycling, also might increase PSA levels. Refrain from such exercise or potential for injury for 48 hours before your PSA test.

Digital Rectal Exam

A digital rectal examination is a vital procedure for detecting prostate problems. During the exam, your physician places a lubricated, gloved finger into your rectum to feel the prostate for abnormalities. This examination of the prostate can elevate PSA levels, so blood for PSA testing should be drawn before digital rectal examination.

Urine Infection, Catheterization and Urinary Retention

Urinary tract or bladder infections, urinary catheterisation, and urinary retention cause an increase in PSA levels. PSA testing should be postponed until four to six weeks after the infection or retention is resolved, and six weeks after the removal of a catheter.

Biopsy and Investigations on Prostate or Bladder

A biopsy, operation or investigation on the prostate or bladder will cause PSA levels to rise. PSA levels can take anywhere between one to six months to return to baseline after these procedures.

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About the Author

An American writer living in the United Kingdom, Christy Mitchinson began writing professionally in 2000, during her career in laboratory science, pathology and research. She has authored training materials, standard operating procedures and patient/clinician information leaflets. Mitchinson is pursuing a Bachelor of Arts in English literature and creative writing with The Open University.