Prostate Specific Antigen, Free Percentage (Includes Free PSA & Total PSA) : ARUP Lab Tests

Prostate Specific Antigen, Free Percentage (Includes Free PSA & Total PSA) : ARUP Lab Tests

Reference Interval: By report Results include: PSA-Free, PSA, PSA-Percent Free
Interpretive Data:	The Roche Modular E170 PSA electrochemiluminescent immunoassay is used. Results obtained with different assay methods or kits cannot be used interchangeably. The Roche Modular E170 PSA method is approved for use as an aid in the detection of prostate cancer when used in conjunction with a digital rectal exam in men age 50 and older. The Roche Modular E170 PSA method is also indicated for the serial measurement of PSA to aid in the prognosis and management of prostate cancer patients. Elevated PSA concentrations can only suggest the presence of prostate cancer until biopsy is performed. PSA concentrations can also be elevated in benign prostatic hyperplasia or inflammatory conditions of the prostate. PSA is generally not elevated in healthy men or men with non-prostatic carcinoma. ARUP uses the Roche Modular E170 Free PSA method in conjunction with the Roche Modular E170 PSA method to determine the free PSA percentage. The free PSA percentage is an aid in distinguishing prostate cancer from benign prostatic conditions in men age 50 and older with a total PSA between 3 and 10 ng/mL and negative digital rectal examination findings. Prostatic biopsy is required for the diagnosis of cancer. (Refer to: JAMA 1998; 279: 1542-1547) In patients with total PSA concentrations of 4-10 ng/mL, the probability of finding prostate cancer on needle biopsy by age in years is: % Free PSA 50-59 years 60-69 years 70 years and older 0-10% 49% 58% 65% 11-18% 27% 34% 41% 19-25% 18% 24% 30% > 25 % 9% 12% 16% Other factors may help determine the actual risk of prostate cancer in individual patients.
Note:	The free percentage is calculated using the total and free PSA results.
CPT Code(s):	84153 PSA, total; 84154 PSA, free
Cross References:	Free Prostate Specific Antigen, PSA, Free