Information on the PSA Blood Test

PSA, or prostate-specific antigen, is a protein the cells of the prostate gland produce. A physician will take a simple blood test and send the sample to a lab to check the levels of PSA in a man's blood. The PSA blood test is used to detect prostate cancer before symptoms develop, but high levels of PSA alone is not enough to tell whether it is cancer or a benign condition, so other tests must be run. The American Cancer Society states that about 192,280 men will develop prostate cancer in 2009, so any test that can improve the chances of survival with early detection is warranted.

Testing Schedule

• The Food and Drug Administration has approved the PSA blood test for men 50 and older, along with men who have already had prostate cancer so that any recurrence of the disease is caught early. Some doctors also advise men with a high risk of developing prostate cancer to begin screening at age 45. Factors that put men at higher risk of developing prostate cancer include being African American, eating a high-fat diet and a family history of the disease.

Levels

• A level of 0 ng/ml to 4 ng/ml (nanograms per milliliter) is considered a normal reading for the PSA blood test. Levels between 4 and 10 ng/ml are considered moderate risk, and anything over 10 ng/ml is considered high risk. Values can vary by age and race to a certain extent. A study by the Mayo Clinic states that older men and African American men will often have higher levels of PSA.

Considerations

• The Prostate Cancer Coalition states that a study showed that some men with PSA levels between 2.5 and 4 ng/ml will develop prostate cancer, and therefore the test level threshold should be lowered.

Determining Results

• A man with PSA blood test levels over 4 ng/ml should go over the results with a physician to determine if cancer is present. The physician will perform a DRE (digital rectal exam) to check for lumps, take a urine sample to rule out urinary tract infections, use x-rays and ultrasound to see structures close to the prostate, and perform a cystoscopy, in which a thin, lighted tube is inserted into the penis to check for blockages. If the results of these tests indicate cancer, a biopsy is the next step.

Warning

• The PSA test does not guarantee a man's survival from prostate cancer because some tumors are too large or grow too fast. False-positive, in which the PSA levels indicates cancer but none is actually present, and false-negative tests, in which cancer is present but results do not indicate high levels of PSA, are also a possibility with the PSA blood test.