PSA Velocity Calculator
PSA Velocity Calculator
Calculate the absolute annual rise in PSA — informative at higher PSA values, though no longer a standalone biopsy trigger.
PSA Velocity
Two PSA values over timePSA 1.2 ng/mL rising to 2.4 ng/mL over 10 months
Formula
- PSA₁, PSA₂
- the earlier and later PSA values, ng/mL
- months ÷ 12
- converts the interval to years so the result is an annual rate
Worked example
PSA 1.2 ng/mL rising to 2.4 ng/mL over 10 months
PSA₂ − PSA₁ = 2.4 − 1.2 = 1.2 ng/mL
10 months ÷ 12 = 0.833 years
1.2 ÷ 0.833 = 1.44 ng/mL/year
PSA velocity thresholds
| Velocity | Interpretation |
|---|---|
| Under 0.35 ng/mL/year | Low |
| 0.35 – 0.75 ng/mL/year | Intermediate |
| Over 0.75 ng/mL/year | Associated with cancer; over 2.0 ng/mL/year in the year before diagnosis linked with poorer outcomes |
Velocity, doubling time, and where guidance has moved
Velocity is the absolute rise in PSA per year, where doubling time is the proportional rise — the two are related but not interchangeable, and velocity tends to be more informative at higher PSA values while doubling time is more sensitive at lower ones, where small absolute changes can still represent rapid proportional growth. A velocity above 0.75 ng/mL/year has historically been associated with prostate cancer, and a rise above 2.0 ng/mL/year in the year before diagnosis has been linked with poorer cancer-specific outcomes.
BE CANDID about where the evidence has moved: major guidelines, including the American Urological Association, have stepped back from using velocity alone as a biopsy indication. The reason is that once age, PSA density and a single current PSA value are accounted for, velocity adds comparatively little independent predictive information, and using it as a standalone trigger generated substantial over-investigation and over-biopsy in men whose PSA fluctuated for benign reasons such as infection or recent ejaculation.
Velocity is only meaningful when calculated properly: at least three measurements over 18 to 24 months, on the same assay, are needed for a stable estimate. A velocity calculated from two values taken weeks apart, or from two different laboratories, is essentially noise and should not drive a clinical decision on its own.
Frequently asked questions
What is PSA velocity used for?
It expresses the absolute annual rise in PSA. It was historically used alongside a single PSA value to flag cancer risk, though guidelines have since stepped back from using it alone to trigger biopsy.
Is PSA velocity still recommended?
Not as a standalone trigger. Major guidelines, including the AUA, no longer recommend biopsy on velocity alone, because it adds little once age, density and a current PSA are considered, and it drove considerable over-investigation.
How many measurements does velocity need?
At least three, spaced over 18 to 24 months, using the same assay. Two values taken close together or on different assays produce an unreliable estimate.
What is the difference between PSA velocity and doubling time?
Velocity is the absolute rise per year; doubling time is the proportional rise. Velocity tends to be more informative at higher PSA values, doubling time at lower ones.
Related calculators
References
- Carter HB et al. Longitudinal evaluation of prostate-specific antigen levels in men with and without prostate disease. JAMA. 1992;267(16):2215–20.
- Vickers AJ et al. An empirical evaluation of guidelines on prostate-specific antigen velocity in prostate cancer detection. J Natl Cancer Inst. 2011;103(6):462–69.