| |
| |
| |
| |
| |
Diagnostics
Measurement of PSA
Measurement of prostate specific antigen (PSA) in the blood is currently the most commonly used screening test for the early detection of prostate cancer. PSA is a protein produced only by the prostate and is found in two forms in the blood. It is either bound to another protein (complex PSA), or found in a free, unattached, state.
- Free PSA is produced by a normal prostate
- Complex PSA is produced mainly by a prostate with cancer.
Whereas free PSA measures the free or unbound PSA in the blood, a test called complex PSA measures the bound form of PSA. The traditional PSA test measures total PSA which includes free PSA and complex PSA. Because complex PSA is produced mainly by cancerous prostate tissue, measurement of complex PSA is a more specific indicator of the presence of prostate cancer than measurement of total PSA.
The PSA test has been limited by its lack of specificity for prostate cancer in the 4-10 ng/ml range (“gray zone”). Only approximately 25% of patients with PSA levels in this range have prostate cancer (75% false positives). Therefore, the detection of prostate cancer in its early stages leads to many unnecessary (benign) biopsies. The currently available test for complex PSA test improves the test specificity from approximately 25% to only 35%.
Egenix’s approach to measurement of complex PSA will more than double the test specificity compared to current approaches for measurement of PSA and complex PSA. The greater specificity of the Egenix complex PSA test will be a clinical breakthrough in the diagnosis of prostate cancer, as it will significantly reduce the number of unnecessary prostate biopsies.