What Affects PSA Results?

Prostate-specific antigen is a protein produced by the prostate gland in males. Doctors use PSA blood tests to screen for and to monitor prostate cancer. Many factors other than prostate cancer, however, can cause an elevation in PSA, making it hard for doctors to rely on the PSA test alone when diagnosing prostate cancer.

Identification

• Normal PSA levels are low in males. A high PSA level, determined by a laboratory test result of higher than 4.0 nanograms of PSA per milliliter of blood, warrants further evaluation.

Potential

• Elevated PSA results can be potentially due to prostate inflammation, infection or benign enlargement with aging.

Time Frame

• PSA blood testing should be performed before or six weeks after other prostate testing procedures like direct rectal exam (DRE) and biopsy, since the stimulation of the prostate by these procedures may cause an elevated PSA result.

Treatments

• Large doses of chemotherapeutic drugs such as cyclophosphamide and methotrexate may cause a decrease or increase in PSA levels.

Considerations

• Rigorous physical activities that involve the prostate, such as biking, may cause a temporary rise of PSA levels and should be avoided before PSA testing.

Expert Insight

• According to the National Cancer Institute, prostate cancer was diagnosed in men with normal PSA levels. The PSA test alone does not give doctors enough information to diagnose or rule out prostate cancer, and interpretation of PSA results should be in the light of findings from other tests as well as other risk factors.