Calbiotech Free PSA Elisa Kit

Product Description

SUMMARY AND EXPLANATION
Human Prostate Specific Antigen (PSA) is a 33 kD serine proteinase which, in human serum, ispredominantly bound to alpha 1-antichymotrypsin (PSA-ACT) and alpha 2-macroglobulin (PSAAMG).Trace amounts of alpha 1-antitrypsin and inter-alpha trypsin inhibitor bound to PSA can also be found. Anyremaining PSA is in the free form (f-PSA).1-3 Current methods of screening men for prostate cancer utilizethe detection of the major PSA-ACT form. Levels of 4.0 ng/ml or higher are strong indicators of thepossibility of prostatic cancer.4 However, elevated serum PSA levels have also been attributed to benignprostatic hyperplasia and prostatitis, leading to a large percentage of false positive screening results.5 Apotential solution to this problem involves the determination of free PSA levels.6-17 Preliminary studieshave suggested that the percentage of free PSA is lower in patients with prostate cancer than those withbenign prostatic hyperplasia.2 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 detectionrates.

PRINCIPLE OF THE TEST
The f-PSA ELISA kit is a solid phase assay based on a streptavidin-biotin principle. The standards,samples and a reagent mixture of Anti-f-PSA Enzyme and Biotin conjugates (conjugate reagent) are addedinto the wells, coated with Streptavidin. f-PSA in the patient™s serum forms a sandwich between two highlyspecific Anti-f-PSA antibodies, labeled with Biotin and HRP. Simultaneously, the biotinylated antibody isimmobilized onto the well through a high affinity Streptavidin-Biotin interaction. Unbound protein andexcess biotin/enzyme conjugated reagent are washed off, by washing buffer. Upon the addition of thesubstrate, the intensity of color developed is directly proportional to the concentration of f-PSA in thesamples. A standard curve is prepared relating color intensity to the concentration of the f-PSA.