Pathology/Lab Coding Alert

Coding for prostate cancer screening and monitoring changed with the addition of new codes to describe testing. A new code in CPT 2001 84152 (prostate specific antigen [PSA]; complexed [direct measurement]) describes a test that directly measures complexed prostate specific antigen (cPSA) using a patented system developed by Bayer Diagnostics. HCPCS G0103 (prostate cancer screening; PSA test, total) was added by HCFA in 2000 to report the use of a PSA test (either complexed PSA or total PSA) for screening prostate cancer for Medicare patients.

Because PSA is a prostate cancer marker, it is a valuable tool for detecting and monitoring the disease. PSA travels in the blood, and the total level is readily measured in a serum specimen. However, a large percentage of PSA is bound, or complexed to protein in the blood, with the remaining portion known as free PSA.

It is the level of cPSA that is most strongly associated with prostate cancer, but until recently, there was no way to measure that fraction directly. Only free and total PSA could be measured, and the ratio of free/total PSA was reported as an approximation of the cPSA. The level of total PSA has often been used as a screening indicator for prostate cancer. As a diagnostic tool, all three assays (total, complexed and free/total ratio) have about the same sensitivity, meaning that they detect the same percentage of cancer patients, explains Lawrence Ferreri, PhD, clinical chemist at Northwest Clinical Laboratory in Northwest Hospital, Seattle. The difference is in the specificity, or the number of false positives. Both complexed PSA and free/total PSA ratio have fewer false positives than the traditional total PSA assay, perhaps 20 to 30 percent fewer, Ferreri says.

This improved specificity is important, because all positive PSA tests must be confirmed by biopsy. The goal is to use a more specific test that will help us avoid a significant number of patients undergoing biopsies that turn out to be negative, Ferreri says.

The data are unclear if the cPSA affords greater specificity than the free/total ratio. However, it is clear that calculating the free/total PSA ratio requires two tests, reported as CPT 84153 (prostate specific antigen [PSA]; total) and 84154 (prostate specific antigen [PSA]; free). Because each test involves analytical variation, the free/total PSA ratio will be inherently less accurate than the direct measure of cPSA, Ferreri says.

Coding for Prostate Cancer Screening

The most common blood test we see ordered for prostate cancer screening is total PSA, says Jean Borgman, MT (ASCP), MBA, director of laboratory services at Northwest Clinical Laboratory in Northwest Hospital, Seattle. The CPT code for this test is 84153, but when reporting the screening test to [...]