- Enter age, sex, serum creatinine, weight, and height (kidney function must be in steady state).
- Enter the target AUC from the regimen (commonly 4–6 mg/mL·min; check the protocol).
- If a measured GFR (iohexol, 99mTc-DTPA, or 51Cr-EDTA clearance, in mL/min) is available, enter it: it becomes the primary input.
- Review the doses by each method and the renal guidance table for other agents.
All computation runs in your browser; no values are stored or transmitted beyond your own device.
When to Use
Use when prescribing or verifying a carboplatin dose, and when a patient with reduced or changing kidney function is due cisplatin, ifosfamide, high-dose methotrexate, pemetrexed, gemcitabine, mitomycin C, or high-dose melphalan.
When NOT to rely on it
Creatinine-based estimates are invalid in acute kidney injury (AKI) and other non-steady states, on dialysis, in pregnancy, under 18 years, and at extremes of muscle mass (cachexia, amputation, paraplegia). The final dose is set by the treating oncologist and pharmacy protocol; this page is a cross-check, not an order.
Pearls & Pitfalls
Why "+25"?
In the Calvert formula, 25 mL/min represents carboplatin's non-renal clearance. Because clearance is in mL/min (not per 1.73 m²), the GFR input must be an absolute value: a measured GFR, or an eGFR de-indexed by body surface area (BSA): eGFR × BSA ÷ 1.73.
Which GFR input
The International Consensus Guideline for Anticancer Drug Dosing in Kidney Dysfunction (ADDIKD) prefers measured GFR for carboplatin, especially with curative intent or when eGFR is above 125 or at or below 45 mL/min/1.73 m²; otherwise BSA-adjusted CKD-EPI eGFR, which predicts drug exposure more accurately than Cockcroft-Gault creatinine clearance (CrCl). Many order sets still use Cockcroft-Gault, so all three are shown.
Pitfalls
(1) Very low creatinine (frail, cachectic, bedridden patients) inflates any creatinine-based GFR and overdoses carboplatin; some institutions round creatinine below 0.7 mg/dL up to 0.7 for Cockcroft-Gault (optional box below). (2) With creatinine-based estimates, the FDA advises capping GFR at 125 mL/min, so the maximum dose is target AUC × 150. (3) Glucocorticoids raise cystatin C and lower cystatin-based eGFR, a common trap during antiemetic or lymphoma regimens.
Calvert Carboplatin Dose
Next Steps
- Curative intent, eGFR above 125 or at or below 45, or unreliable creatinine: request a measured GFR before cycle 1 if available (for example, 99mTc-DTPA plasma clearance); ADDIKD strongly recommends measured GFR before high-dose methotrexate.
- Recalculate each cycle from fresh creatinine and weight; cisplatin, ifosfamide, and methotrexate can lower GFR between cycles.
- Cisplatin: 2–4 L saline over 4–6 hours, magnesium 8–16 mEq, avoid concurrent nephrotoxins; consider carboplatin or oxaliplatin in high-risk patients (ADQI 2026).
- High-dose methotrexate: urine alkalinization to pH above 7.1, hydration, stop interacting drugs (for example, proton pump inhibitors, trimethoprim-sulfamethoxazole, penicillins, NSAIDs), leucovorin by level, and glucarpidase for delayed clearance with AKI.
- Read the onconephrology guide; compare methods with the EKFC vs CKD-EPI calculator and Cockcroft-Gault.
Evidence
Formulas
Calvert: dose (mg) = target AUC (mg/mL·min) × [GFR (mL/min) + 25]. Derived and prospectively evaluated with 51Cr-EDTA GFR (Calvert et al., 1989).
BSA-adjusted eGFR: CKD-EPI 2021 eGFR × BSA ÷ 1.73; BSA by Mosteller = √(height cm × weight kg ÷ 3600).
Cockcroft-Gault: CrCl = (140 − age) × weight ÷ (72 × creatinine mg/dL), × 0.85 if female.
ADQI 34 general dosing in reduced GFR (Lentini et al., 2026)
| Agent | Reduced kidney function | Hemodialysis |
|---|---|---|
| Cisplatin | CrCl 50 to <60: ↓ about 25%; 40 to <50: ↓ about 50%; <40: avoid (palliative-intent recommendations differ) | Avoid; if used, give after HD with dose ↓ about 50% |
| Ifosfamide | CrCl 46–60: ↓ about 20%; 31–45: ↓ about 25%; <30: ↓ about 30% | Not recommended; some removal |
| High-dose methotrexate | Regimen-specific; e.g., hyper-CVAD: creatinine 1.5–2 mg/dL ↓ about 25%; >2 mg/dL ↓ about 50% | Not recommended |
| Pemetrexed | Contraindicated if CrCl <45 | Limited data; generally avoid |
| Gemcitabine | CrCl <30 raises hematologic toxicity risk; no standard adjustment | Dialyze 6–12 hours after the dose |
| Mitomycin C | CrCl <30: avoid | Not removed |
| Melphalan (high dose, before autologous transplant) | CrCl 30–59: 200 → 140 mg/m² (or full dose); <30: 140 mg/m² | Not dialyzable; give after HD |
