What factors affect prostate specific antigen (PSA) levels in the blood?

Prostate-specific antigen (PSA) is a protein produced by the prostate. Elevated PSA levels may indicate the presence of prostate cancer, benign prostatic hyperplasia (BPH) -- enlarged prostate, or prostatitis -- inflammation or infection of the prostate. A PSA test measures the level of this protein in the blood.

Factors that typically produce a substantial or sustained rise in PSA include:

• Benign prostatic hyperplasia (BPH)
• Prostatitis
• Urinary tract infections
• Prostate biopsies
• Prostate surgery
• Prostate cancer

Factors that sometimes produce a small or temporary rise in PSA include:

• Ejaculation
• A digital rectal examination
• A urinary catheter and bladder examination
• Vigorous bike riding
• Warm climates
• Changes in labs or testing methods
• Hepatitis
• Bypass surgery

Factors that typically produce a substantial and/or sustained decrease in PSA include:

• Therapy with finasteride (Proscar) or dutasteride (Avodart)

Factors that sometimes produce a small and/or temporary decrease in PSA include:

• Therapy with a statin drug
• Therapy with a nonsteroidal anti-inflammatory drug (NSAID)
• Obesity
• Changes in laboratories or testing methods
• Diet

Some things can cause the PSA level to remain low or drop, even when cancer is present. For example, obese men tend to have lower PSA levels than men at a healthy weight. Some medicines (including those used to treat baldness and urinary symptoms) and herbal remedies may also lower PSA, potentially masking cancer. That's why it's important to tell your doctor about all of the medications and supplements you take.