GFR + Contrast Media Dose

Renal function check and iodinated contrast volume planning before CT

Patient parameters

Age (years)

Sex

Weight (kg)

Height (cm)

Serum creatinine

Iodine concentration

Target iodine load (g I / kg)

CKD-EPI 2021 (race-free, recommended)

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mL/min/1.73m²

Cockcroft-Gault: — mL/min

MDRD: — mL/min/1.73m²

CKD stage: —

—

CKD-EPI 2021: \( eGFR = 142 \times \min(\frac{S_{cr}}{\kappa},1)^{\alpha} \times \max(\frac{S_{cr}}{\kappa},1)^{-1.200} \times 0.9938^{age} \times (1.012\;\text{if female}) \)
Cockcroft-Gault: \( CrCl = \dfrac{(140 - age) \times weight}{72 \times S_{cr}} \times (0.85\;\text{if female}) \)
Contrast volume: \( V = \dfrac{\text{iodine load (g/kg)} \times weight}{\text{concentration (mg/mL)}} \times 1000 \)

Stage	eGFR	Contrast guidance (ESUR/ACR)
G1	≥ 90	Normal — no restriction
G2	60–89	Mildly decreased — no restriction
G3a	45–59	Hydration recommended; minimise dose
G3b	30–44	Use cautiously; consider alternatives, hold metformin 48h
G4	15–29	Avoid if possible; only if benefit > risk
G5	< 15	Avoid (unless dialysis-dependent)

Inker LA et al. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. NEJM 2021;385:1737-1749. doi:10.1056/NEJMoa2102953
ESUR Guidelines on Contrast Agents v10.0 (2018). esur.org/guidelines
ACR Manual on Contrast Media 2024 — contrast-induced acute kidney injury thresholds.
Bae KT. Intravenous contrast medium administration and scan timing at CT. Radiology 2010;256:32-61. doi:10.1148/radiol.10090908