What is Prostate-specific Antigen (PSA)?
Prostate Specific Antigen (PSA) is a protein, a member of the human kallikrein gene family, produced by certain cells in the prostate gland. It plays an important role in increasing sperm mobility and liquefaction of seminal fluid by proteolytic cleavage of gel-forming proteins in seminal fluid.
PSA is produced in the glandular epithelium of prostate and is secreted in seminal fluid in high concentrations. A very little amount of PSA flows through the bloodstream, thus its concentration remains low in the blood. Some amount of it is also found in peri-utheral and anal glands, cells of male urethra, breast milk and urine. If the PSA levels are found to be higher than what are normally defined for a respective age group or if there is a sudden use in the levels of PSA without a diagnosed cause, it is recommended to undergo testing to rule out prostate cancer or presence of other abnormal cells in prostate.
Test Principle of Prostate-specific Antigen (PSA)
Electrochemiluminescene immunoassay (ECLIA), more specifically sandwich immunoassay, is used in the ROCHE Modular EEE for analysis of PSA levels. The analysis takes place over a total of 18 minutes, as follows:
- 1st incubation:
This step involves the formation of a sandwich complex, by the interaction of 20 μl. of test sample, a ruthenium complex-labeled monoclonal PSA-specific antibody and a monoclonal biotinytatal PSA-specific antibody.
- 2nd incubation:
The interaction of biotin and streptavidin leads to binding of complex to the solid phase after addition of streptavidin-coated micropartides.