Part One: What is PSA and What it Does

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Part one of a four-part series on the PSA test to demystify the most feared blood marker in men.


Part one: What is PSA and what it does

Part two: Benign reason’s why PSA goes up

Part three: PSA as a screening tool for prostate cancer

Part four: PSA after prostate cancer treatment


No blood test provokes more anxiety than the PSA test.

Not cholesterol, not fasting glucose and, not Triglycerides make a man shake his knees more than the P – S -A test.

What is PSA?

For many, PSA stands for Patient Stimulated Anxiety.

All kidding aside, PSA is for Prostate Specific Antigen, a misnomer since it is not prostate-specific. PSA molecule is also found in a women’s blood who have cervical, uterine and breast cancer (Pummer et al. 1992, Mohajeri et al. 2011).

How Does PSA Work?

PSA is a protease. Any suffix ending with –ase is an enzyme and breaks things down or digests something. For example, lipase digests lipids (fats), sucrase digests sucrose (sugar), etc., like PSA, break a specific protein in men called seminogelin.

Seminogelin is what causes semen to clump up after ejaculating, causes the sperm to immobilize, thus interfering with conception.

You may have noticed that semen clumps up initially after ejaculation. Within a few minutes, it liquefies due to the function of the molecule PSA. This “anti-clumping” aspect is essential for procreation. Sperm cells swim better when they are loose and free.

The purpose of PSA (other than to get you nervous) is for making babies.



Pummer K, Wirnsberger G, Pürstner P, Stettner H, Wandschneider G. False positive prostate specific antigen values in the sera of women with renal cell carcinoma. J Urol. 1992 Jul;148(1):21-3.

Mohajeri A, Zarghami N, Pourhasan Moghadam M, Alani B, Montazeri V, Baiat A, Fekhrjou A.Prostate-specific antigen gene expression and telomerase activity in breast cancer patients: possible relationship to steroid hormone receptors. Oncol Res. 2011;19(8-9):375-80.

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by Dr. Geo

2 comments… add one
  • Tina 04/12/2018, 3:05 PM

    My husband had a vasectomy in his early thirties. He has no symptoms but his psa tests from August was 4.07, then again in November at the urologist it was 4.03. He had another in March and it was 4.5. Could the vasectomy cause the psa to be higher? He also tested low in testosterone and is having hot flashes and terrible night sweats. Urologist said to come back for another psa test in six months. Is this normal?

    • Dr. Geo 04/17/2018, 10:15 AM

      Tina, I don’t think his current PSA is related to the vasectomy. There are mixed conclusions to whether or not vasectomies contribute to prostate cancer formation – the most current studies suggesting no association. There are many non-cancer reasons why PSA increases. All the best to you and your husband.


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