Calculators · Urology · Formula

PSA doubling time (PSADT)

Also called PSADT, PSA kinetics

Time for PSA to double, by log-linear regression of PSA on time (PSA Working Group method).

ng/mL
ng/mL
ng/mL
ng/mL

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Formula and scoring

PSADT = ln 2 ÷ slope of the least-squares line of ln(PSA) against time. Working Group: at least 3 values ≥0.2 ng/mL, at least 4 weeks apart, all values from the last 12 months.

Exam and ward pearls

  • The Working Group method uses natural log and linear regression — not just the first and last value.
  • PSADT drives decisions in biochemical recurrence after prostatectomy or radiotherapy.

When not to rely on it

  • Do not mix values from different PSA assays, and do not use values taken during or soon after androgen deprivation.

Source

  1. Arlen PM, Bianco F, Dahut WL, et al. Prostate Specific Antigen Working Group guidelines on prostate specific antigen doubling time. J Urol. 2008;179(6):2181-5. doi:10.1016/j.juro.2008.01.099 · PMID 18423743

Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.

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