# Carboplatin dose calculation by the Calvert formula and kidney function

Source: https://onco.cc/protocols/carboplatin-dose-calculation/  
OnCo record `carboplatin-dose-calculation` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Carboplatin is not dosed by your size but by how well your kidneys clear it. The team picks a target exposure (the 'AUC', often 5 or 6) and multiplies it by your kidney filtration rate plus 25. Your kidney function is either measured with a special test or estimated from a blood test, and the newest international guidance prefers the measured test when treatment aims to cure.

## Summary

The Calvert formula (1989) gives the total dose in mg as target AUC x (GFR + 25). It was derived and validated with GFR measured by 51Cr-EDTA clearance, and the US label prints it with that note. The kidney function fed into it is where practice differs.

ADDIKD (2025), the first international consensus on anticancer drug dosing in kidney dysfunction, prefers directly measured GFR, not standardised to body surface area, especially with curative intent, extremes of body size or muscle mass, amputation or paraplegia, or an eGFR above 125 or at or below 45 ml/min/1.73 m2. Where measured GFR is not feasible, it recommends eGFR by CKD-EPI de-indexed to the patient's own BSA (clinical consensus; strong). KDIGO 2024 says non-indexed eGFR may be indicated at extremes of body weight for narrow-therapeutic-range drugs, and its text names carboplatin. Much of the world still uses Cockcroft-Gault creatinine clearance, which overestimates GFR by 10 to 20% and, with modern IDMS-standardised creatinine assays, can overdose: in a UK cohort of 2,471 patients, 25.5% of Cockcroft-Gault doses were more than 20% off against 18.6% for BSA-adjusted CKD-EPI (Janowitz 2017).

ADDIKD advises against lowering the target AUC because of reduced kidney function, and against recalculating each cycle unless kidney function changes by more than 20% or the patient's condition changes. In the UK, adult doses are then banded to national tables (BOPA 2025) and the pharmacist checks the AUC calculation at verification.

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: Calvert formula; carboplatin AUC dosing; carboplatin dose by GFR; AUC 5 carboplatin; carboplatin GFR; EDTA GFR for carboplatin; carboplatin Cockcroft-Gault

## Connected records

- key papers: [Carboplatin dosage: prospective evaluation of a simple formula based on renal function](https://onco.cc/key-papers/paper-calvert-j-clin-oncol/)
- protocols: [Anticancer treatment prescribing and pharmacy verification before each cycle](https://onco.cc/protocols/sact-prescribing-and-pharmacy-verification/), [Body surface area and weight-based dose calculation for anticancer drugs, including full doses in obesity](https://onco.cc/protocols/body-size-based-dose-calculation/), [Dose banding of anticancer drugs](https://onco.cc/protocols/dose-banding-of-anticancer-drugs/), [Renal dose adjustment of anticancer drugs in reduced kidney function](https://onco.cc/protocols/renal-dose-adjustment-of-anticancer-drugs/)
- drugs: [Carboplatin](https://onco.cc/drugs/carboplatin/), [Iohexol](https://onco.cc/drugs/iohexol/)
- technologies: [Carboplatin dosing by kidney function: the Calvert formula and how kidney function is measured](https://onco.cc/technologies/carboplatin-calvert-dosing/)
- terms: [Pharmacokinetics (PK), half-life and exposure](https://onco.cc/terms/pharmacokinetics/)
- ideas: [Compare carboplatin dosed by BSA-adjusted CKD-EPI eGFR with Cockcroft-Gault on toxicity and response](https://onco.cc/ideas/idea-upgrade-carboplatin-gfr-estimate-outcome-study/)

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