What is contrast-induced nephropathy?

CIN is an acute decline in kidney function — typically a rise in serum creatinine ≥0.5 mg/dL or ≥25% within 48 hours of iodinated contrast administration. It is one of the most common causes of hospital-acquired acute kidney injury.

What is the Mehran risk score?

Published by Mehran et al. in 2004 (JACC), the Mehran score assigns weighted points to eight clinical variables. Scores ≤5 carry ~7.5% CIN risk; scores ≥16 carry >57% risk and a ~12.6% dialysis risk.

How is eGFR used when creatinine is not available?

The tool accepts either serum creatinine or eGFR. When only eGFR is available, it back-calculates an approximate creatinine equivalent for scoring. Entering measured serum creatinine directly is more accurate.

What creatinine threshold triggers scoring points?

The Mehran score awards 4 points for serum creatinine >1.5 mg/dL and 2 additional points per 100 mL of contrast volume above 100 mL. Diabetes combined with elevated creatinine further increases the score.

Is this tool a substitute for clinical judgment?

No. The Mehran score is a validated educational aid, not a clinical order. Always confirm values with measured labs, consult current institutional protocols, and involve nephrology for high-risk patients.

Contrast-Induced Nephropathy Risk Calculator

Name: Contrast-Induced Nephropathy Risk Calculator
Availability: InStock
Author: Nham Vu

Calculate the Mehran risk score to estimate the probability of contrast-induced nephropathy (CIN) and need for dialysis after iodinated contrast exposure.

Patient Risk Factors

Kidney Function

Serum Creatinine (mg/dL)

Contrast Volume (mL)

Volume used: +1 pt per 100 mL above first 100 mL

Clinical Risk Factors

Hypotension (SBP <80 mmHg ≥1 hr requiring vasopressors) +5 pts IABP use (intra-aortic balloon pump) +5 pts CHF (NYHA class III–IV or history of pulmonary edema) +5 pts Age >75 years +4 pts Anemia (Hct <39% men / <36% women) +3 pts Diabetes mellitus +3 pts

Enter patient data and click Calculate to see the Mehran CIN risk score.

Mehran Risk Score

CIN Probability

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Dialysis Risk

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Score 0Score 25

Score Breakdown

Mehran Risk Tiers

Score	Risk Tier	CIN Risk	Dialysis Risk
≤5	Low	7.5%	0.04%
6–10	Moderate	14.0%	0.12%
11–15	High	26.1%	1.09%
≥16	Very High	>57.3%	12.6%

Educational reference only. Based on Mehran R et al., JACC 2004;44(7):1393–1399. Not a substitute for clinical judgment or institutional protocols.

Summary

Calculate the Mehran risk score to estimate the probability of contrast-induced nephropathy (CIN) and need for dialysis after iodinated contrast exposure.

How it works

Enter the patient's baseline serum creatinine or estimated GFR, age, and sex.
Select applicable risk factors: hypotension, IABP use, CHF, anemia, and diabetes.
Enter the planned contrast volume in mL.
Each factor contributes a weighted point value to the total Mehran score.
The score maps to one of four CIN risk tiers with estimated probability ranges.
Review the result and dialysis risk estimate to guide pre-procedure hydration or nephrology consultation.

Use cases

Pre-procedure risk stratification before coronary angiography or PCI.
Assess CIN risk prior to CT angiography in patients with comorbidities.
Determine need for prophylactic IV hydration or N-acetylcysteine protocol.
Support cardiology or radiology decision-making on contrast volume limits.
Educate medical students and residents on CIN risk factors.
Document pre-procedure kidney risk assessment in patient records.

Frequently Asked Questions

Last updated: 2026-07-22 · Reviewed by Nham Vu