HE4 Human Epididymis Protein 4 Elisa Test Kit

INTENDED USE

The free PSA assay is an enzyme-linked immunosorbent assay (ELISA) for the in vitro quantitative determination of free prostate-specific antigen (fPSA) in human serum.

Summary

PSA is a 32 kDa single chain glycoprotein serine protease with a chymotrypsin like speci city produced by the secretory epithelium of the prostate gland.1 PSA is normally secreted into the seminal uid and plays a functional role in the cleavage of the seminal vesicle proteins and the liquefaction of the seminal coagulum.2 Only low levels of PSA are normally present in the blood stream, and increasing serum concentrations indicate prostatic pathology, including benign prostatic hyperplasia and cancer of the prostate. Determination of PSA is now widely used for detection and management of patients with prostatic cancer and considered as the superior serological marker for cancer of the prostate.3 PSA has been shown to form stable complexes with different antiproteases and the dominating portion of PSA in patient serum occurs in complex with α1- antichymotrypsin (PSA-ACT).4 However there are large variations in the relation between Free PSA and PSA ACT complex between different individuals. A number of studies have found that the proportion of Free PSA is higher in benign prostatic disease as compared to prostatic cancer.4,5 The Free PSA EIA is an assay for specific determination of Free PSA without cross reactivity with PSA- ACT complex.6

Test principle

Sandwich principle.

Total duration of assay: 80 minutes. • Sample, PSA-specific antibody coated microwells and enzyme labeled Anti-Free PSA monoclonal antibody are combined. • During the incubation, Free PSA presents in the sample is allowed to react simultaneously with the two antibodies, resulting in the Free PSA molecules being sandwiched between the solid phase and enzyme-linked antibodies. • After washing, a complex is generated between the solid phase, the Free PSA within the sample and enzyme-linked antibodies by immunological reactions. • Substrate solution is then added and catalyzed by this complex, resulting in a chromogenic reaction. The resulting chromogenic reaction is measured as absorbance. • The absorbance is proportional to the amount of Free PSA in the sample.