Name Free PSA RIA kit
Category Name Cancer RIA kits
Test 100
Principle Immunoradiometric assay
Detection Range 0-20 ng/mL
Sample 25 µl serum
Sensitivity 0.03 ng/mL
Total Time ~120 min
Shelf Life 45 Months from the manufacturing date

Materials provided with free-PSA RIA Test Kit:

1. Coated Tubes: Anti –FPSA monoclonal Antibody (100 tubes)

2. Anti-FPSA monoclonal antibody Labelled with I 125 (Tracer I125)

3. PSA test reference standard set, contains 0, 0.5, 1, 2.5,5, 20, ng/ml, ready for use

4. Serum Diluent : BSA – PBS

5. Control serum: FPSA in serum with preservatives(1Vial, 0.5 ml)

6. Washing Solution (Concentrted): Tween 20solution

Materials Required, not Provided:

1. Precision pipettes

2. Gama counter


Human Prostate Specific Antigen (PSA) is a 33 kD serine proteinase which, in human serum, is predominantly bound to alpha 1-antichymotrypsin (PSA-ACT) and alpha 2-macroglobulin (PSA-AMG). Trace amounts of alpha 1-antitrypsin and inter-alpha trypsin inhibitor bound to PSA can also be found. Any remaining PSA is in the free form (f-PSA). Current methods of screening men for prostate cancer utilize the detection of the major PSA-ACT form. In the Free PSA RIA kit, Levels of 4.0 ng/ml or higher are strong indicators of the possibility of prostatic cancer. However, elevated serum PSA levels have also been attributed to benign prostatic hyperplasia and prostatitis, leading to a large percentage of false positive screening results. A potential solution to this problem involves the determination of free PSA levels. Preliminary studies have suggested that the percentage of free PSA is lower in patients with prostate cancer than those with benign prostatic hyperplasia. Thus, the measurement of free serum PSA in conjunction with total PSA, can improve specificity of prostate cancer screening in selected men with elevated total serum PSA levels, which would subsequently reduce unnecessary prostate biopsies with minimal effects on cancer detection rates.

Principle of the assay:

Immune radiometric assay (IRMA) kit, evaluates free PSA based on the one step non-competitive reaction. In this type of assay, the method employs two highly specific monoclonal anti-free PSA antibodies which recognize two different epitopes of the molecule. One antibody is coated on solid phase (coated tube), the other, specific for the free PSA and labelled with Iodine-125, is used as a tracer. Both of these antibodies react with free PSA antigens which are present in standard, control serum and the sample. Unspecific materials are removed in the washing step. The amount of activity form in the tube has a direct relationship to the free PSA concentration. free PSA standards with known concentrations are tested with the unknown samples in which the concentration of unknown samples is achieved based on the standard curve of the counted amount against concentration of free PSA.