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 original score assigns 2 points for eGFR 40–59, 4 for 20–39, and 6 for below 20 mL/min/1.73 m². It does not require back-calculating creatinine.

What creatinine threshold triggers scoring points?

The original score awards 4 points for serum creatinine above 1.5 mg/dL and 1 point for each complete 100 mL of contrast volume.

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

Calculate the original Mehran score for contrast-associated kidney injury risk after PCI; results reflect the 2004 derivation cohort.

Patient Risk Factors

Kidney Function

Serum Creatinine (mg/dL)

Contrast Volume (mL)

Volume used: +1 pt per complete 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

The Mehran risk score estimates the likelihood of contrast-induced nephropathy (CIN) — defined as a rise in serum creatinine ≥0.5 mg/dL or ≥25% within 48 hours of contrast administration. It combines eight weighted clinical variables into a total score, which maps to four risk tiers. This tool is intended for educational and pre-procedure planning purposes only; clinical decisions require direct patient assessment.

How it works

Enter the patient's baseline serum creatinine or eGFR.
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.
Interpret the historical cohort estimate alongside current cardiology and institutional guidance.

Use cases

Pre-procedure risk stratification before coronary angiography or PCI.
Review the variables used in the original PCI risk model.
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: 2026-06-15 · Reviewed by Nham Vu