| Scenario | Inputs | Key outputs |
|---|---|---|
| Example A | 170 cm, 70 kg, male, 55 y, SCr 1.0, 75 mg/m² | BSA ≈ 1.82 m², base ≈ 136 mg, CrCl typically ≥60, rounded dose ≈ 135–140 mg |
| Example B | 160 cm, 60 kg, female, 68 y, SCr 1.3, 40 mg/m² | BSA ≈ 1.63 m², base ≈ 65 mg, CrCl lower, apply renal factor, rounded dose per policy |
| Example C | 180 cm, 110 kg, male, 50 y, SCr 1.1, 100 mg/m² (AdjBW) | BSA ≈ 2.33 m², base ≈ 233 mg, CrCl weight method changes factor selection |
Body Surface Area
Mosteller method estimates BSA from height and weight.
Creatinine Clearance
Cockcroft–Gault estimates CrCl using age, SCr, and weight.
Dose calculation
This tool multiplies dose basis by BSA, then applies factors.
- Enter height, weight, age, sex, and serum creatinine.
- Select the dose basis in mg/m² from your protocol.
- Choose a weight method for CrCl if clinically required.
- Set a manual factor for protocol modifications or prior toxicity.
- Pick a rounding increment that matches pharmacy policy.
- Click Calculate Dose to view results above the form.
- Use the CSV/PDF buttons to save the calculation record.
Dose basis and regimen context
Cisplatin is often ordered as mg/m² with schedules that vary by disease site and intent. This calculator converts your chosen mg/m² basis into a milligram dose using BSA, then surfaces the base dose and the rounded dose used for preparation. It supports consistent documentation when protocols specify weekly dosing, every-three-week dosing, or split dosing across consecutive days. Capture the cycle day, planned hydration, and antiemetic pathway in the notes field to keep the record clinically meaningful during review. Record regimen name to avoid cross-protocol dosing errors later.
Body surface area calculation
BSA is calculated with the Mosteller equation: BSA = √((height(cm) × weight(kg)) / 3600). Mosteller is commonly used because it is simple and closely aligned with other standard BSA methods across typical adult ranges. The tool reports BSA to three decimals to make later verification and order reconciliation easier, especially when weights change between clinic and infusion visits.
Renal function estimation and adjustment
Nephrotoxicity risk makes renal assessment central to cisplatin planning. The tool estimates creatinine clearance using Cockcroft–Gault and lets you choose actual, ideal, or adjusted body weight for the equation. A conservative renal factor is suggested from CrCl thresholds and shown explicitly, so you can align the calculation with local guidance or trial rules. Consider repeating creatinine near administration and documenting magnesium and potassium plans when risk is elevated.
Manual factor and clinical modifiers
Protocols may require dose reductions after significant toxicities or for patient-specific risks such as neuropathy, ototoxicity, frailty, or cumulative exposure. The manual factor provides a transparent multiplier (e.g., 0.75 for a 25% reduction). This keeps modifications visible and auditable rather than hidden in handwritten notes, and helps reconcile delivered dose intensity across cycles.
Rounding, exports, and safe handoffs
Rounding to a defined increment can reduce compounding variability and support vial-based preparation. The output shows the unrounded and rounded dose, plus the calculation path and key intermediate values (BSA, CrCl, adjustment factors). CSV and PDF exports capture inputs, intermediate values, and the final recommendation for review by oncology, nursing, and pharmacy teams during verification and handoffs. Always confirm contraindications, hearing status, neuropathy symptoms, and local maximum-dose policies before administration.
FAQs
1) Which BSA formula is used?
Mosteller: BSA = √((height(cm) × weight(kg)) / 3600). It is widely used for adult oncology dosing workflows and is easy to verify at the bedside.
2) Why does creatinine clearance change with weight method?
Cockcroft–Gault includes weight, so actual, ideal, or adjusted weight can shift CrCl. Some protocols define the method in obesity, edema, or low muscle mass to reduce bias.
3) Does the renal factor replace institutional guidance?
No. The renal factor is a conservative prompt. Follow your protocol, pharmacy guidance, and specialist review, especially near eligibility cutoffs or when nephrotoxic co-medications are present.
4) What is the manual factor for?
It applies planned modifications, such as reductions for prior toxicities or regimen-specific rules. Example: 0.80 applies a 20% reduction to the base dose before rounding.
5) Should I round the dose?
Use your pharmacy policy. Rounding can improve compounding consistency and reduce waste, but clinical trials and some centers require exact dosing or narrow limits for rounding.
6) Can I use this for pediatrics?
This tool is built for adult-style inputs and Cockcroft–Gault CrCl. Pediatric dosing commonly uses different renal equations and protocol rules; follow pediatric oncology references.