Total prostate specific antigen

I believe everyone knows that the prostate is a male-specific sex gland organ, and the prostate antigen is secreted by the prostate tissue cells, so it is also called prostate-specific antigen. It mainly exists in the prostate cells of men, and there is also some content in semen and blood. This article will explain in detail the relevant biological knowledge of prostate-specific antigen, and everyone can learn about it together.

Prostate-specific antigen exists in three main forms in serum: ① free prostate-specific antigen (fPSA), accounting for 10% to 30% of total prostate-specific antigen (tPSA); ② a complex formed by the combination of prostate-specific antigen and α1-antichymotrypsin (PSA-ACT); ③ a complex formed by the combination of prostate-specific antigen and α2-macroglobulin (PSA-α2M). The latter two are also called complex prostate-specific antigen (cPSA). The main physiological function of prostate-specific antigen is to prevent semen from coagulation. It has extremely high tissue and organ specificity and is currently the preferred marker for diagnosing prostate cancer.

Clinical significance

If serum tPSA and fPSA are elevated, but tPSA/fPSA is decreased, then the diagnosis of prostate cancer should be considered to improve the specificity and accuracy of the diagnosis. Slight elevations in serum tPSA and fPSA may also be seen in prostatitis, prostatic hypertrophy, nephritis, prostatic polyps, and diseases of the urogenital system. When tPSA or fPSA is used alone to diagnose prostate cancer, the influence of benign prostate diseases cannot be ruled out.

Normal value reference range

Total prostate-specific antigen (tPSA): <4.0μg/ml; free prostate-specific antigen (fPSA): ml; fPSA/tPSA: >0.25.

Notes

1. Prostate massage, prostate biopsy, rectal examination, indwelling catheter, cystoscopy, etc. should be avoided before blood specimen collection.

2. The PSA values ​​measured by different methods are different and cannot be mixed.

3. For prostatitis, PSA should be measured 8 weeks after symptoms disappear.

4. Long-term cycling can easily lead to elevated serum PSA levels.

5. Hormone therapy can affect the expression of PSA and reduce PSA levels.

6. Blood samples should be centrifuged within 3 hours of collection and the serum should be refrigerated for no more than 24 hours.

7. Age has an impact on serum PSA levels, which tend to increase with age.

Check the population

1. Men aged 50 years and above with lower urinary tract symptoms.

2. Men with a family history of prostate cancer.

3. Men with abnormal digital rectal examination, clinical manifestations (such as fractures, bone pain, etc.) or abnormal imaging.

4. Patients who have been diagnosed with prostate cancer also need to have their serum PSA tested regularly during follow-up visits after treatment.