This is a brief overview of information related to FDA's approval to market this product. See the links below to the Summary of Safety and Effectiveness and product labeling for more complete information on this product, its indications for use, and the basis for FDA's approval.
Product Name: Dimension® Free Specific Antigen (FPSA) Flex® Reagent Cartridge
Manufacturer: Dade Behring, Inc.
Address: P.O. Box 6101, Newark, Delaware 19714
Approval Date: January 24, 2003
Approval Letter: http://www.accessdata.fda.gov/cdrh_docs/pdf3/P020027a.pdf
What is it? The Free Prostate-Specific Antigen (FPSA) test is typically performed at the same time as a Total Prostate-Specific Antigen (TPSA) test to help distinguish between cancerous and benign (non-cancerous) prostate conditions.
The FPSA test measures the amount of PSA that is not attached to other substances (free-floating) in the blood. The Total Prostate-Specific Antigen (TPSA) test measures both the amount of PSA that is attached to proteins in the blood and PSA that is in the free-floating form. Once both tests are completed, a doctor compares the FPSA result to the TPSA result to determine the ratio of free-floating to TPSA. If the ratio of FPSA to TPSA is less than 0.19, the patient is more likely to have prostate cancer.
It takes about 18 minutes for the laboratory to determine the results of each test. Blood is drawn by a needle (venipuncture) and aside from the needle prick this procedure should be painless.
When does a doctor use this test? A doctor uses an FPSA test to help diagnose prostate cancer and distinguish between cancerous conditions and benign conditions. A doctor will order this test when the patient:
- is a male who is 50 years or older,
- has a PSA level between 4 nanograms per milliliter (ng/mL) and 10 ng/mL, and
- has a prostate gland that appears of normal size and texture during a digital rectal exam.
A doctor may perform a FPSA test at the same time or after a TPSA test.
When should it not be used? A doctor should not diagnose prostate cancer using only the results of the FPSA test. Normally, a doctor will follow up any worrisome results with a biopsy. During a biopsy, a doctor:
- removes a small amount of prostate tissue and
- examines it under a microscope to determine if the growth benign or cancerous.
How does it work? A laboratory measures FPSA and TPSA in the same sample of a man’s blood. During an FPSA test:
- chemicals are mixed with the liquid part of a man’s blood (serum),
- an analyzer measures the results and calculates the level of FPSA in the man’s serum, and
- the laboratory or doctor calculates the fraction of FPSA to TPSA (ratio).
- If the ratio of FPSA to TPSA is less than 0.19, the man’s high TPSA suggests that he may have prostate cancer
- If the ratio of FPSA to TPSA is more than 0.19, the man’s high TPSA is more likely due to a non-cancerous prostate condition.
What will it accomplish? As a man ages, his prostate has a greater chance of developing tumors. Some tumors are not cancerous, such as benign prostatic hyperplasia. Some tumors are cancerous. Both kinds of growths seem to increase PSA, but cancer seems to decrease the ratio of FPSA/TPSA.
The FPSA test helps a doctor to estimate the likelihood that a patient has prostate cancer and whether he needs a biopsy.
Additional information: Summary of Safety and Effectiveness and labeling is available at: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cftopic/pma/pma.cfm?num=P020027