What Does Low Free PSA Mean?

The prostate is a small gland in the male reproductive system, almost equivalent to the size of a walnut, but cancer is this region is the second leading cause of cancer death in American men. According to the American Cancer Society, one in six men will be diagnosed with prostate cancer, and 1 in 36 men will die from prostate cancer. These statistics illustrate why early detection is a necessity, and testing the levels of Protein-Specific Antigen (PSA) is one of the detection methods.

About PSA

• The prostate is responsible for producing the fluid that composes part of a male's semen. The protein PSA makes up most of this fluid and is considered a tumor marker by the National Cancer Institute. A PSA test will assist doctors with patient diagnosis. Generally, high PSA levels indicate the presence of cancer in the prostate, but high PSA levels alone do not mean the patient has cancer as there are other factors to consider.

PSA Test

• When used in conjunction with the digital rectal exam, the PSA test is an FDA approved prostate cancer early detection method, and can also be used to monitor patients who have a prostate cancer record. Of the PSA produced by the prostate, a small amount can be found in the bloodstream. There are two types of PSA located in the bloodstream, free PSA and complexed PSA (cPSA). The test, however, does not distinguish between the two types but instead gives the total amount of PSA in the bloodstream.

  Normal PSA levels are considered to be a ratio of four nanograms per millileter of blood. Anything above 10 nanograms call for more extensive prostate cancer testing. However, this measurement system leaves a borderline area, where levels between four to 10 nanograms require clarification. In this instance, a free PSA test may be ordered. Of note, PSA levels below four nanograms does not mean a patient is cancer-free as PSA levels tend to vary from person to person.

Low Free PSA

• While cPSA is attached to other proteins, free PSA is not and can loosely drift in the bloodstream. For those patients in the borderline measurement area, the free PSA test will reveal if free PSA levels are poor, and low levels of free PSA may indicate a higher risk of prostate cancer. Patients with free PSA levels that are 10 percent or less will require a biopsy, and patients with levels between 10 and 25 percent will be considered for a biopsy. Since biopsies are typically painful and may involve infection or bleeding, these percentage limits help to reveal which patients truly need a biopsy.

Other Factors

• In diagnosing a patient with prostate cancer, the PSA test can be beneficial, but the test is only one step out of many in the diagnosis process. A variety of factors can cause PSA levels to drop, such as medicinal products, herbal substances and weight. As such, some doctors will also conduct PSA tests over a number of months to monitor levels because rising trends over a period of time may not only signal prostate cancer, but also indicate the velocity, or aggressiveness, of the cancer.