Preparation for PSA analysis


Table of contents

  • When should I take a blood test for PSA?
  • Forms of prostatic specific antigen
  • Preparation for PSA analysis
  • The causes of changes in PSA

Typically, a man in the body contains a small amount of prostate-specific antigen (PSA). This antigen is a protein that is synthesized by the prostate gland. With inflammation, enlargement, cancer and other prostate diseases, the amount of PSA in the blood increases. Determine the amount of antigen can be by using a blood test. As with other tests, the PSA test must be properly prepared. Therefore, further on, how to prepare for the analysis of PSA.


When should I take a blood test for PSA?

An analysis of the prostatic specific antigen reveals the development of a cancer or non-cancer disease. The limit of the PSA test is 4 ng / ml. If a man has an increase in the norm to 10 ng / ml, the probability of having prostate cancer reaches 25%. If this figure exceeds the mark of 10 ng / ml, then the probability of detection of cancer pathology increases to 75%.

Until recently, the PSA value below 4 ng / ml was considered the norm, but recent studies have shown that this erroneous opinion, since the test results below the norm may also indicate a variety of diseases in the body men. The possibility of detection in this case of oncology is approximately 15%.

The main indications for the PSA test are:

  • suspicion of prostate cancer after other examinations (for example, after ultrasound);
  • monitoring the progression or regression of PCG cancer and the effectiveness of the prescribed treatment;
  • patients who are prescribed radical anti-tumor treatment - in this case it is necessary to take a blood test for PSA at least once every 4 months;
  • a prophylactic examination of the male over the age of 45, the detection of changes in the level of PSA.

Forms of prostatic specific antigen

In the blood, this antigen is in two forms: free and associated with antiproteases. The level of the first form is approximately 10% of the total amount of PSA. About 90% of the antigen is in conjunction with alpha1-antichymotrypsin (ACT). A certain amount of PSA is associated with alpha2-MG. It is impossible to determine this form of antigen by the standard method, because the PSA molecule is located inside the complex. In this case, more complex diagnostic methods are used.

Therefore, speaking of PSA, it means its free and AHT-related form.In prostate cancer, the amount of bound antigen increases, and the free antigen decreases. The content of the free fraction in the blood in PCa is much lower than its concentration in a benign tumor (p & lt; 0001). In this way, the principle of differential diagnosis of prostate cancer and hyperplasia is implemented.

Preparation for PSA analysis

Each patient should know and adhere to all the rules for preparing for the analysis of prostatic specific antigen, otherwise the test results will be incorrect, which will lead to the necessity re-surrender.

Preparation for the delivery of the SPA should include such items:

  1. Abstinence from ejaculation for at least 2 days before delivery.
  2. To conduct the analysis not earlier than in 3 days after deep massage of a prostate.
  3. If a patient is given a transurethral resection, this test can be performed no earlier than 6 months after the procedure.
  4. If the patient is made TRUS, then the analysis can be done only after 7 days.
  5. After a prostate biopsy, at least 6 weeks must pass before the test for a prostatic specific antigen is passed.

The causes of changes in PSA

When decoding the results of the analysis, age ranges should be taken into account. Boundary values ​​of different age groups are controversial, not all specialists agree that the accepted age framework is better than the simple adoption of a normal PSA level, ng / ml. The table shows the upper limits of the total PSA, adjusted for the age group.

Age limits The boundary value (ng / ml)
40-50 ,
50-60 ,
60-70 ,
70 and more ,

The total prostatic specific antigen may increase slightly with prostate adenoma, acute diseases, infection in the urinary tract, chronic inflammatory processes. The PSA test is most effective when it is necessary to confirm or refute prostate cancer.


In Russia, 75% of men with prostate cancer, this disease is diagnosed in the last stages, when it is almost impossible to cure it. If cancer is detected in the early stages, modern treatment can be quite effective. In this regard, all men need to regularly take this test.

Another reason for the increase in PSA may be a disruption in the functioning of prostate cells. Tumor cells can synthesize a prostatic specific antigen in smaller amounts than in healthy tissues. Therefore, such a test can be called specific for normal prostate cells, but not for cancer.

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The increase in the number of tumor elements has a high impact on antigen production, as a result of which the test results can vary significantly.

The level of PSA may decrease under the influence of some medications used for drug treatment of prostate adenoma. With a long admission of "Dutasteride" and "Finasteride the antigen level decreases by a factor of 2, which should be taken into account when deciphering the results of the analysis for PSA.

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PSA analysis is very important in the diagnosis and treatment of prostate cancer. This test allows you to evaluate the success of treatment. A decrease in the level of PSA can talk about quality and effective treatment.