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KDIGO AKI staging (pediatric)

The current measured serum creatinine. Accepts mg/dL or µmol/L. Drives the ×-baseline ratio and the ≥ 4.0 mg/dL Stage-3 threshold.

The patient's baseline creatinine (known outpatient value, or a dynamic 7-day baseline). Needed for the ×-baseline ratio and the ≥ 0.3 mg/dL rise. Accepts mg/dL or µmol/L.

Weight-indexed urine output in mL/kg/h, over the KDIGO collection window. < 0.5 is oliguric; < 0.3 is the Stage-3 threshold. Compute as volume ÷ weight ÷ hours.

Estimated GFR in mL/min/1.73 m² (bedside Schwartz: 0.413 × height[cm] ÷ creatinine[mg/dL]). Only supply for a patient < 18 years: < 35 forces Stage 3 (pediatric-only KDIGO branch).

Initiation of dialysis / CRRT. When yes, KDIGO assigns Stage 3 regardless of the creatinine and urine-output axes.

Independent clinical validation: pending

Two independent clinical validators will be named here once review is complete.

Validator slot open 1
Validator slot open 2

How it is calculated

KDIGO stage = the higher (maximum) of two independent axes. Serum-creatinine axis: Stage 1 if current creatinine is 1.5–1.9× baseline or has risen ≥ 0.3 mg/dL; Stage 2 if 2.0–2.9× baseline; Stage 3 if ≥ 3.0× baseline, or ≥ 4.0 mg/dL, or renal replacement therapy has started, or (in a child) estimated GFR < 35 mL/min/1.73 m². Urine-output axis: Stage 3 if < 0.3 mL/kg/h, Stage 1 if 0.3 to < 0.5 mL/kg/h (the KDIGO duration windows are assumed met). The reported stage is the maximum of the two axes; if neither axis is met the stage is 0 (AKI definition not met).

Limitations and notes

Not a summed score: the serum-creatinine and urine-output axes are evaluated independently and the MAXIMUM stage governs — treating it as additive is wrong. This is a pediatric calculator: the eGFR < 35 mL/min/1.73 m² branch is exclusive to patients < 18 years in KDIGO Table 2 and is applied here whenever an eGFR is supplied, so do not enter an eGFR for an adult. Baseline creatinine is the hardest input — KDIGO does not fix a single pediatric baseline-creatinine method [NEEDS SOURCE for a KDIGO-endorsed pediatric baseline rule]; the baseline supplied here drives the ratio-based and ≥ 0.3 mg/dL-rise stages, and the ≥ 0.3 mg/dL rise is applied as (current − baseline) rather than a timed 48-hour delta. Urine output is entered as a single sustained rate: because a rate alone cannot distinguish the KDIGO duration windows (Stage 1 is < 0.5 mL/kg/h for 6–12 h; Stage 2 is < 0.5 mL/kg/h for ≥ 12 h), the < 0.5 (but ≥ 0.3) band is reported as Stage 1 (the minimum-guaranteed stage, not over-staged); assigning Stage 2 from urine output requires a confirmed ≥ 12 h window not captured by a single rate. The pediatric eGFR branch is contested for young children — GFR rises developmentally and the bedside Schwartz equation was validated ~1–16 y, so do not extrapolate to neonates without a neonatal-specific estimator [NEEDS SOURCE for a neonatal eGFR method]. The predecessor pediatric system pRIFLE (Akcan-Arikan 2007) is a separate instrument and is not reproduced here. Creatinine SI↔conventional conversion reuses the shared clinical factor (1 mg/dL = 88.42 µmol/L); KDIGO's rounded 26.5 / 353.6 µmol/L equivalents of the 0.3 / 4.0 mg/dL cutoffs are not used because the mg/dL values are authoritative. Higher KDIGO stage is associated with higher mortality and RRT risk in the outcome literature, but the staging itself is a classification, not a treatment threshold — keep any display descriptive. The per-input plausible min/max are input-validity guardrails, not published KDIGO thresholds.

Accepted input ranges

  • Current serum creatinine — 0.1–15 mg/dL
  • Baseline serum creatinine — 0.1–15 mg/dL
  • Urine output (sustained rate) — 0–10 mL/kg/h
  • Estimated GFR (pediatric, bedside Schwartz) — 1–200 mL/min/1.73m2
  • Renal replacement therapy started

References

  1. KDIGO Acute Kidney Injury Work Group. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2(1):1–138. Definition = Rec 2.1.1; staging = Rec 2.1.2 / Table 2.DOI 10.1038/kisup.2012.1
  2. Palevsky PM, et al. Reading between the (guide)lines — the KDIGO practice guideline on acute kidney injury in the individual patient. Kidney Int. 2014;85(1):49–61.Source
  3. Schwartz GJ, Muñoz A, Schneider MF, et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol. 2009;20(3):629–637.PMID 19158356DOI 10.1681/ASN.2008030287
  4. Palevsky PM, et al. KDOQI US Commentary on the 2012 KDIGO Clinical Practice Guideline for Acute Kidney Injury. Am J Kidney Dis. 2013;61(5):649–672.PMID 23499048DOI 10.1053/j.ajkd.2013.02.349

Version and changelog

v1.0.0 · Renal and metabolic

  • 2026-07-25 v1.0.0 — Initial release: KDIGO 2012 AKI staging (Stage 0–3) as the max of the serum-creatinine and urine-output axes, with the pediatric eGFR < 35 and RRT Stage-3 branches.

Important

For use by qualified health professionals as an informational and educational aid. It supports clinical judgment and does not replace it. Verify every result independently before making a clinical decision. This is not a medical device.