What is the KDIGO definition of AKI?

KDIGO 2012 defines AKI as any of: serum creatinine rise ≥0.3 mg/dL within 48 hours, ≥1.5× baseline within 7 days, or urine output <0.5 mL/kg/hr for ≥6 hours.

How is the baseline creatinine chosen?

Use the lowest creatinine value from the prior 7 days (for acute staging) or the prior 3 months if no recent values are available. If no prior value is known, some guidelines use a back-calculated eGFR of 75 mL/min/1.73m².

What defines Stage 3?

Stage 3 is creatinine ≥3× baseline, creatinine ≥4.0 mg/dL with an acute rise ≥0.5 mg/dL, initiation of renal replacement therapy, or urine output <0.3 mL/kg/hr for ≥24 hours or anuria for ≥12 hours.

Does this tool replace clinical judgment?

No. This is a reference aid. Clinical context — volume status, medications, prior chronic kidney disease — must be considered. Always confirm staging with the treating physician.

Which units should I use?

Creatinine in mg/dL (US standard). Weight in kg for urine output calculation. If your values are in µmol/L, divide by 88.4 to convert to mg/dL.

KDIGO AKI Staging

Name: KDIGO AKI Staging
Availability: InStock
Author: Nham Vu

Classify acute kidney injury severity (Stage 1, 2, or 3) using serum creatinine change or urine output per KDIGO 2012 criteria.

Creatinine Criteria

Baseline Creatinine (mg/dL)

Lowest value in prior 7 days (or 3 months if unavailable)

Current Creatinine (mg/dL)

Urine Output Criteria (optional)

Urine Output Rate (mL/kg/hr)

Duration of Oliguria (hours)

How long has UO been at this rate?

Enter creatinine values and click Calculate AKI Stage to see the result.

AKI Stage (KDIGO 2012)

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Criterion Breakdown

Criterion	Value	Stage Met

Clinical Note

The final AKI stage is the highest stage met by any single criterion. Stage 3 also applies if renal replacement therapy (RRT) was initiated regardless of creatinine level. This tool does not account for RRT initiation — record that separately.

KDIGO 2012 Staging Reference

Stage	Serum Creatinine	Urine Output
Stage 1	1.5–1.9× baseline OR ≥0.3 mg/dL increase (within 48 h)	<0.5 mL/kg/hr for 6–12 h
Stage 2	2.0–2.9× baseline	<0.5 mL/kg/hr for ≥12 h
Stage 3	≥3.0× baseline OR ≥4.0 mg/dL (acute rise ≥0.5 mg/dL) OR RRT initiated	<0.3 mL/kg/hr for ≥24 h OR anuria ≥12 h

Source: KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2(1):1–138.

Summary

Classify acute kidney injury severity (Stage 1, 2, or 3) using serum creatinine change or urine output per KDIGO 2012 criteria.

How it works

Enter the baseline serum creatinine (the lowest value in the prior 7 days or 3 months).
Enter the current serum creatinine measured today.
Optionally enter urine output (mL/kg/hr) and the observation period (hours).
The calculator applies KDIGO 2012 thresholds for absolute rise, percentage rise, and urine output.
The highest stage from any criterion is reported as the final AKI stage.

Use cases

Rapidly stage AKI at the bedside or during rounds.
Determine whether a patient meets KDIGO Stage 3 criteria for renal replacement therapy consideration.
Document AKI severity for clinical notes, coding, and quality metrics.
Educate trainees on KDIGO thresholds through interactive entry.
Compare creatinine and urine output criteria simultaneously.
Identify oliguria-driven AKI even when creatinine has not yet risen.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu