Our Methodology — The Gault Standard
The Gault Standard is our methodological seal: every calculation follows the validated Cockcroft–Gault lineage, every clinical value is cited to a primary source, and every clinical page is reviewed by a credentialed clinician before it is marked production-ready.
The Historical Anchor
Donald Cockcroft and Henry Gault published the creatinine clearance equation in the journal Nephron in 1976, deriving it from a cohort of hospitalised patients and validating the estimate against measured clearance. That paper is the lineage our calculators trace back to. Dr. Henry Gault (1925–2003) was a Canadian nephrologist; he is the historical namesake and methodology anchor for this site — he is not a current medical reviewer, and no content here is attributed to him as a reviewer. Modern eGFR work has moved on to the race-free CKD-EPI 2021 equation and KDIGO guidance, both of which we follow for staging.
How We Verify Clinical Values
- Formula coefficients are checked against the original publications and the National Kidney Foundation.
- Normal ranges and CKD cutoffs follow KDIGO and NKF; ranges that vary by laboratory are noted as such.
- Drug thresholds are checked against the FDA label and standard renal-dosing references, then cited.
- The calculator engine is unit-tested against published worked examples before any tool ships.
The Calculator Engine Is Tested
Each formula lives in a pure, typed module with its own unit tests. Before a calculator goes live, those tests confirm it reproduces the worked examples published by reference sources for the same inputs — so a Cockcroft–Gault result here matches a Cockcroft–Gault result computed by hand or by an established reference tool. Unit conversions, body-weight rules, and edge cases are tested the same way. A formula stays flagged for clinician review even when its tests pass; passing tests prove the arithmetic, not the clinical appropriateness.
Clinician Review and Refresh
Fact-checking and citation raise trust, but they do not replace human sign-off. A credentialed clinician reviews each page and signs off on its clinical values; until that sign-off, those values are flagged as reviewer-pending and the page is not presented as authoritative. After publication, every clinical page is re-checked on a three-to-six-month cycle so that changing guidelines, updated drug labels, and new evidence are reflected rather than left to drift. See our medical reviewers.
Why We Cite Primary Sources
On a medical site, a number carries no weight without a source. We attach a real citation to every clinical value — a formula coefficient, a normal range, a drug threshold — and we prefer the primary publication or a recognised body such as the National Kidney Foundation, KDIGO, or an FDA label over a secondary summary. When two reputable sources disagree, we follow the more authoritative one, note the discrepancy, and cite both. This is how a reader, or a clinician checking our work, can trace any claim back to where it came from rather than taking it on trust.