How to prepare for the 'PSA' test: rules for taking it

Prostate-specific antigen (PSA) is a protein produced by the cells of the prostate gland. The PSA test is used for the early detection of prostate cancer and for monitoring during testosterone therapy. However, PSA reacts not only to a tumor: its level is raised by inflammation, mechanical irritation of the gland and even sexual activity. The editorial team explains how to prepare so as not to get a false alarm or false reassurance.

What PSA is and why to test for it

PSA is an enzyme from the group of serine proteases that liquefies seminal fluid. Its main part remains in the prostate secretion, and only a small amount enters the blood. When the structure of the gland is disrupted — by a tumor, inflammation, injury or an increase in volume — more PSA enters the blood.

That is precisely why PSA is specific to prostate tissue but not to cancer. An elevated level may be a consequence of benign hyperplasia, prostatitis, a urinary tract infection or recent mechanical impact. And conversely: low PSA does not guarantee the complete absence of a tumor, as the PCPT study showed.

In the blood, PSA exists in two forms: bound to proteins and free. The laboratory can determine total PSA and, if necessary, free PSA and calculate their ratio. A lower proportion of free PSA is more often associated with cancer, so this indicator helps the doctor decide whether further examination is needed.

For athletes, the test has additional significance: the Endocrine Society recommends determining PSA before starting testosterone therapy and monitoring it during treatment in men of the appropriate age, since androgens stimulate the growth of prostate tissue.

Factors that falsely raise PSA

The greatest significance belongs to factors that mechanically irritate the prostate or cause inflammation in it. They can temporarily raise PSA, sometimes above the threshold at which the doctor considers a biopsy.

Ejaculation can temporarily raise PSA. Studies have shown that the level rises over the first hours and returns to baseline after one to two days. Therefore most laboratories recommend abstaining from sexual activity for at least 48 hours before the test.

Prolonged cycling and other types of mechanical pressure on the perineum can theoretically irritate the prostate. Study data are contradictory, but for reliability the editorial team advises not planning long cycling sessions, motorcycle riding or horseback riding for 48 hours before the test.

Urological interventions have the strongest effect: prostate biopsy, cystoscopy, bladder catheterization, transrectal ultrasound. After a biopsy, PSA may remain elevated for several weeks, so the test is usually postponed for at least 6 weeks. A digital rectal examination has a much smaller effect, but it is advisable to draw blood for PSA before it.

Acute prostatitis and urinary tract infections can raise PSA several-fold. If there were symptoms — pain, burning during urination, fever — the test should be postponed until treatment is complete and repeated after a few weeks.

Medications and hormones that change the level

5-alpha-reductase inhibitors — finasteride and dutasteride — lower PSA by about half after 6–12 months of use. They are prescribed for benign prostatic hyperplasia, and finasteride in lower doses — for androgenetic alopecia. If you take such drugs, be sure to inform your doctor: they must interpret the result taking this effect into account.

Testosterone therapy, on the contrary, can raise PSA, especially in the first months in men with initially low testosterone. Endocrine Society guidelines provide for monitoring PSA 3–12 months after the start of treatment and thereafter in accordance with screening recommendations.

The use of anabolic steroids without medical supervision also affects the prostate and PSA, as well as other indicators that require monitoring. The editorial team emphasizes: such use is associated with health risks, and the doctor needs to know about it for correct interpretation.

High-dose biotin, popular in supplements for hair and nails, can distort the results of some immunoassays that use the streptavidin-biotin system. Laboratories usually advise stopping high-dose biotin at least 48–72 hours before the test.

Rules for taking it: a step-by-step plan

1. 48 hours before — abstain from ejaculation, prolonged cycling and intense training that loads the perineum.
2. 48–72 hours before — stop high-dose biotin (after agreeing with the doctor).
3. After a biopsy or cystoscopy — wait at least 6 weeks; after prostatitis — until full treatment.
4. Draw blood before a digital rectal examination or ultrasound, not after.
5. Note on the referral the use of finasteride, dutasteride, testosterone or other hormones.
6. For tracking trends — take the test at one laboratory: results of different methods may differ.

Fasting for total PSA is usually not required, however many laboratories advise drawing blood in the morning, after a few hours without food, especially if other indicators are determined at the same time.

If free PSA is to be determined, it is important that the sample be processed quickly: the free form is less stable, and prolonged storage of whole blood can lower it.

Intense strength training in itself is not a proven factor for a significant increase in PSA, but the day before the test it is better to limit yourself to moderate activity. This is a general rule for most biochemical tests: it reduces the variability of results and makes the trend more reliable.

Finally, it is worth recording for yourself the date and conditions of each test: whether there was sexual activity, training, drug use. Such a brief journal will help the doctor distinguish a real change in PSA from the effect of preparation.

How the result is interpreted

A single «norm» for PSA does not exist. Traditionally a level up to 4 ng/mL was considered acceptable, but modern urological guidelines take into account age, prostate volume, trend, PSA density, the proportion of free PSA, family history and MRI data.

A single elevated result is not grounds for an immediate biopsy. The European Association of Urology recommends repeating the test after a few weeks under standard conditions in the case of moderately elevated PSA, since a significant proportion of increases turn out to be temporary.

The value of PSA rises significantly when there is a trend: a stable value over years and a rapid increase are completely different clinical situations. That is precisely why identical preparation for each test is so important.

The decision on PSA screening is recommended to be made jointly with a doctor after discussing the benefits and risks, in particular the risk of overdiagnosis and unnecessary procedures.

Editorial conclusions

PSA is sensitive to mechanical irritation and inflammation of the prostate, so before the test it is worth abstaining for 48 hours from ejaculation and prolonged cycling.

After urological interventions and prostatitis the test is postponed; finasteride and dutasteride lower PSA, while testosterone can raise it — the doctor must know about this.

An elevated result should be repeated under standard conditions, and interpreted taking into account age, trend and other data.

We also recommend reading our articles on preparing for the total testosterone test, on cortisol, and on the lipid profile.

References

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2. Thompson IM, Pauler DK, Goodman PJ, et al. Prevalence of prostate cancer among men with a prostate-specific antigen level ≤4.0 ng per milliliter. N Engl J Med. 2004;350(22):2239–2246.
3. Andriole GL, Bostwick DG, Brawley OW, et al. Effect of dutasteride on the risk of prostate cancer. N Engl J Med. 2010;362(13):1192–1202.
4. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744.
5. Tchetgen MB, Song JT, Strawderman M, et al. Ejaculation increases the serum prostate-specific antigen concentration. Urology. 1996;47(4):511–516.
6. Wei JT, Barocas D, Carlsson S, et al. Early detection of prostate cancer: AUA/SUO guideline part I: prostate cancer screening. J Urol. 2023;210(1):46–53.