How this calculator works
PSA density divides serum PSA by prostate volume. You can enter a measured volume or estimate it from three perpendicular dimensions with the ellipsoid model. PSA is entered as micrograms/L, numerically equal to ng/mL. Infection, enlargement, medicines and measurement technique can affect the inputs. This page does not use a density threshold to decide on biopsy. The result is an estimate for information only and is not medical advice.
Formula
PSA density = PSA (ng/mL) / prostate volume (mL). Ellipsoid volume = pi × length × width × height / 6. PSA = density × volume; volume = PSA / density.
Worked example
PSA 4 ng/mL divided by a 40 mL prostate gives 0.1 ng/mL per mL. PSA 6 with volume 30 mL gives 0.2.
Advertisement
Frequently asked questions
Is a millilitre the same as a cubic centimetre?
Yes. A 40 cm³ prostate has a volume of 40 mL.
Does a high density diagnose cancer?
No. It is one part of a wider assessment, including imaging, examination and clinical history.
Can zero PSA be entered?
Yes when calculating density or recovering PSA. Recovering volume or a dimension requires positive PSA and density.