Prostate-specific antigen (PSA) is secreted by the epithelial cells of the prostate gland, found at low levels in healthy men but often elevated in prostate cancer or other prostate disorders. Most PSA in the blood is bound to serum proteins; only a small amount is not protein-bound and is called “free PSA.” In men with prostate cancer, the ratio of free (unbound) PSA to total PSA is low. The risk of cancer increases if the free to total PSA ratio is less than 25%. The lower the ratio, the greater the probability of prostate cancer.

There are several organizations promoting the use of fPSA testing, however there are some differing recommendations on when a fPSA test should be performed: The US FDA approved the use of % fPSA to screen men with PSA levels of 4-10 ng/mL, while the European Association of Urology (EAU) recommends its use in men with PSA levels of 2-10 ng/mL before prostate biopsy. The National Comprehensive Cancer Network (NCCN) suggests % fPSA in men with no prior biopsy and PSA levels higher to 3 ng/mL, or prior negative biopsy with continued suspicion of cancer.

  • Quantitative, non-subjective results
  • Increased sensitivity and broader detection range compared to rapid tests


  • Working range: 0.1-30.0 ng/mL


Intra-lot Precision

  • Intra-lot precision was determined by testing of fPSA reference materials using 10 test devices from the same lot.  CV ≤ 15%.

Inter-lot Precision

  • Inter-lot precision was determined by testing of fPSA reference materials using 30 test devices from three consecutive lots randomly (10 test devices from each lot). CV ≤ 20%.


  • fPSA control materials with three different concentrations were tested by every lot of test device, and the deviations were within ±15%.


  • A serial concentration of fPSA reference materials at 0.1-30.0 ng/mL was tested, and the correlation coefficient (R) is ≥ 0.9900.

Reagents and Materials provided:

  1. Individually sealed foil pouches containing:
    1. One test device
    2. One desiccant
  2. Detection buffer tubes
  3. SD card
  4. Instructions for Use

Materials required but not provided:

  1. Clock or timer
  2. RaFIA Immunofluorescence Analyzer
  3. RaFIA Immunofluorescence Incubator