|  | Cancer | Prostate Cancer

Levels of the PSA Test

Levels of blood protein prostate-specific antigen or PSA can help doctors detect early signs of prostate cancer, a leading cause of cancer among American men. By measuring PSA blood levels before symptoms appear, doctors can screen for prostate cancer up to 10 years earlier than a rectal exam, according to John Hopkins Medicine. While a PSA test cannot diagnose cancer, abnormal levels may indicate whether you have a prostate problem and may help guide cancer treatment.

  1. About PSA Levels

    • Experts agree PSA levels can vary among men and with age. For that reason there is no "normal" PSA level that signals whether you are likely to have or not have prostate cancer. In general, the higher your PSA level, the greater your risk of having prostate cancer. As a guideline, the National Institute of Health suggests values above 2.5 nanograms of PSA per milliliter or ng/mL of blood for men younger than 50 are concerning, while values above 3.5 and 4.5 ng/ml for men in their 50s and 60s, respectively, require further investigation (See References 2).

    Normal or Low Levels

    • A PSA test is not without its drawbacks. A normal PSA level is not a foolproof indicator that you do not have prostate cancer. A test may miss the presence of cancer because most prostate cancers grow slowly over decades, taking years before doctors see elevated PSA levels.

      Some prostate medications and dietary supplements may alter PSA levels by lowering, and therefore disguising, true values. PSA tests on men undergoing hormone therapy for prostate cancer may also show low levels during or immediately after treatment.

    High Levels

    • Elevated PSA levels are not a clear indicator of prostate cancer. In fact, high PSA levels are commonly linked to an infected or enlarged prostate. If you recently had a tube inserted into your bladder to drain urine, had a urinary tract infection, have a large prostate or ejaculated 48 hours before a PSA test, your results may show higher PSA levels. According to the MayoClinic.com, only about 25 percent of men who show elevated PSA levels actually have prostate cancer (See References 3).

    Risks

    • PSA test results may detect slow-growing tumors that may not cause symptoms or become life-threatening. An estimated 29 to 44 percent of men who have PSA tests showing abnormal levels that signal prostate cancer have tumors that would not cause symptoms over their lifetime, the MayoClinic.com reports (See References 4). The resulting anxiety, along with the costly and time-consuming follow-up tests and treatments, can cause undue stress. Additionally, prostate cancer treatment may causes difficulties with bowel movements, having or maintaining an erection and urine control.

    Improving Test Accuracy

    • Scientists continue to research ways to improve the accuracy of the PSA test so that doctors can better interpret test results. This includes examining the relationship between the size of a man's prostate and PSA levels; whether PSA is attached to a protein molecule in the blood since high levels of attached PSA are linked to prostate cancer; and changes in PSA levels over time. According to a 2006 article by H. Ballentine Carter in the "Journal of the National Cancer Institute," men who had a greater change in PSA levels per year had a greater risk of dying from prostate cancer compared to men with a less significant change in PSA levels (See References 5).

Prostate Cancer - Related Articles