AKI and CKD Staging Pathway (KDIGO)
AKI and CKD against KDIGO, with the CKD-EPI 2021 risk grid · v1.2- Start by saying whether this is an acute injury or established chronic disease. The two arms of this tool read the same creatinine differently.
- Acute kidney injury: it applies the KDIGO criteria to the rise from baseline, to the urine output, or to both.
- Chronic kidney disease: it uses the race-free CKD-EPI 2021 equation and pairs the eGFR with the albuminuria category, which is what turns a number into a KDIGO stage.
- It also reports Cockcroft-Gault clearance, because that is the figure most drug labels were written against.
- Both arms assume the creatinine is steady. During an evolving injury it is not, and the kinetic GFR calculator is the tool for that.
- Children and adolescents. Both equations here were derived in adults.
- The cause of the kidney failure. It stages, and a stage is not a diagnosis: the answer comes from the history, the urine sediment, the drug chart and the ultrasound.
- Whether the abnormality has lasted the three months that define chronic kidney disease, which a single creatinine cannot establish. A first low eGFR in a patient with no old records may be acute, chronic, or acute on chronic.
- The decision to dialyse.
- The dose adjustment of any particular drug, beyond naming which figure a label was written against.
1. Acute or Chronic
2. Demographics and Serum Creatinine
3. Albuminuria (Optional Here, Required for a KDIGO Stage)
A urine protein-creatinine ratio is none of these three, and it cannot stand in for an albumin ratio. If you have the raw urine albumin and urine creatinine, the UPCR & UACR Calculator will work them into a ratio you can enter here. Leave this section empty and what you get back is a G stage on its own, not a KDIGO stage.
An evolving injury needs a different equation. Both equations here assume the creatinine is steady, and while an injury is still moving it is not. The Kinetic GFR Calculator exists for that. The rest of what this tool leaves out is in the scope box at the top of the page.
1. Why CKD Is Staged on Two Axes
CKD was once staged on eGFR alone, which hides the patient who is still filtering normally and is losing the filter while you watch. Albuminuria marks active glomerular endothelial damage and podocyte effacement, so it reports damage happening now, where eGFR reports what has already gone. A patient with a normal eGFR of 90 (G1) and heavy albuminuria (A3) carries a higher risk of progression to kidney failure and of cardiovascular death than a patient with an eGFR of 50 (G3a) and no albuminuria (A1).
2. The KDIGO Prognostic Heatmap
Practice advisory, KDIGO 2024. The KDIGO 2024 CKD guideline replaced the 2012 edition in March 2024, and two points bear on how this output should be read. First, where cystatin C is available, KDIGO now asks that the GFR category be assigned from the combined creatinine and cystatin C equation (eGFRcr-cys) rather than creatinine alone, because the combined equation separates the risk stages more reliably. This engine computes CKD-EPI 2021 creatinine-only, which remains correct and is what KDIGO expects when cystatin C has not been measured; treat a creatinine-only stage near a category boundary as provisional and confirm it with cystatin C where the result would change management. Second, KDIGO 2024 moves the emphasis from the staging grid towards individual risk prediction, using the Kidney Failure Risk Equation for 2 and 5 year risk of kidney failure. The heatmap still holds, but two patients in the same cell can carry materially different absolute risk.
| eGFR Category (G-Stage) | A1 (< 30 mg/g or mg/24h) | A2 (30-300 mg/g or mg/24h) | A3 (> 300 mg/g or mg/24h) |
|---|---|---|---|
| G1 (≥ 90) | Low Risk | Moderate Risk | High Risk |
| G2 (60-89) | Low Risk | Moderate Risk | High Risk |
| G3a (45-59) | Moderate Risk | High Risk | Very High Risk |
| G3b (30-44) | High Risk | Very High Risk | Very High Risk |
| G4 (15-29) | Very High Risk | Very High Risk | Very High Risk |
| G5 (< 15) | Very High Risk | Very High Risk | Very High Risk |
3. True AKI Against Pseudo-AKI
| True acute kidney injury | Pseudo-AKI, creatinine secretion blockade | |
|---|---|---|
| Mechanism | An actual decline in glomerular filtration rate: pre-renal (hypovolaemia), intrinsic (acute tubular necrosis, nephrotoxins) or post-renal (obstruction) | A drug blocks tubular secretion of creatinine at the OCT2 and MATE1 transporters in the proximal tubule. The actual GFR remains completely normal |
| Drugs | Nephrotoxins in the intrinsic group | Trimethoprim, in cotrimoxazole; cimetidine; cobicistat |
| What the bloods show | A rising creatinine accompanied by a rising urea, electrolyte derangement such as hyperkalaemia, and usually altered urine output | An isolated rise in creatinine, usually a 0.3 to 0.5 mg/dL bump at most. Urea normal, no electrolyte derangement, resolves entirely when the drug is stopped |
| Next step | Urinary indices, FeNa and FeUrea, to separate pre-renal from intrinsic | Do not stop beneficial therapy or reflexively order dialysis |
Fenofibrate is not one of these. It raises creatinine too, but not by secretion blockade alone, and a genuine fall in measured GFR has been reported on it. A rise on fenofibrate needs a measured clearance rather than reassurance.
4. The Nephrotoxins a Patient Will Not Volunteer
Much of the unexplained acute-on-chronic renal failure seen in Indian practice comes from two sources the patient will not volunteer. The first is over-the-counter NSAID use, diclofenac and aceclofenac above all, bought without a prescription and taken for months for a bad knee. The second is unregulated alternative and Ayurvedic preparations, bhasmas among them, some of which carry heavy metals. Ask about both by name: a patient asked whether they take any medicines will say no, and will mean the ones a doctor wrote down. NSAIDs constrict the afferent arteriole, and in a patient whose perfusion already depends on prostaglandin-mediated dilatation that is enough to drop the GFR hard.
5. Why Cockcroft-Gault Is Still Printed
Cockcroft-Gault was published in 1976, before creatinine assays were standardised, and it takes raw body weight into its numerator. In an obese or fluid-overloaded patient a good deal of that weight is not muscle, so the equation credits the kidney with a clearance it does not have.
- KDIGO asks for CKD-EPI when staging disease, and CKD-EPI is the number to stage with.
- Dosing is a separate question. The renal dose adjustments carried on FDA labels for drugs such as vancomycin and digoxin were derived against Cockcroft-Gault, so a label that says to reduce the dose below a given clearance means clearance as Cockcroft-Gault measured it.
- That is why the tool prints Cockcroft-Gault next to the stage, and it is the only thing that figure is there for.
Abbreviations: ACEi (Angiotensin-Converting Enzyme Inhibitor) · AER (Albumin Excretion Rate) · AKI (Acute Kidney Injury) · ARB (Angiotensin Receptor Blocker) · ATN (Acute Tubular Necrosis) · BUN (Blood Urea Nitrogen) · CG (Cockcroft-Gault) · CKD (Chronic Kidney Disease) · CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) · CrCl (Creatinine Clearance) · DOAC (Direct Oral Anticoagulant) · eGFR (Estimated Glomerular Filtration Rate) · eGFRcr-cys (Estimated Glomerular Filtration Rate from Creatinine and Cystatin C) · FDA (United States Food and Drug Administration) · FeNa (Fractional Excretion of Sodium) · FeUrea (Fractional Excretion of Urea) · GFR (Glomerular Filtration Rate) · K⁺ (Potassium) · KDIGO (Kidney Disease: Improving Global Outcomes) · LMWH (Low Molecular Weight Heparin) · MATE1 (Multidrug and Toxin Extrusion Protein 1) · NSAID (Non-Steroidal Anti-Inflammatory Drug) · OCT2 (Organic Cation Transporter 2) · OTC (Over-the-Counter) · RAAS (Renin-Angiotensin-Aldosterone System) · RRT (Renal Replacement Therapy) · SGLT2 (Sodium-Glucose Cotransporter-2) · UACR (Urine Albumin-to-Creatinine Ratio)
References
- Inker LA, et al. New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737-1749.
- Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314. [Current edition; supersedes the 2012 CKD guideline]
- Stevens PE, Ahmed SB, Carrero JJ, et al. Executive summary of the KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease: known knowns and known unknowns. Kidney Int. 2024;105(4):684-701.
- KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl. 2013;3(1):1-150. [Superseded 2024]
- KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2(1):1-138.
- Tangri N, Stevens LA, Griffith J, et al. A predictive model for progression of chronic kidney disease to kidney failure (Kidney Failure Risk Equation). JAMA. 2011;305(15):1553-1559.
- Indian CKD Guideline Workgroup, Indian Society of Nephrology. Indian Chronic Kidney Disease Guidelines. Indian Society of Nephrology; December 2013.
How to Cite This Tool
DOIhttps://doi.org/10.5281/zenodo.22401636
AMA Style:Umakanth S. AKI and CKD Staging Pathway (KDIGO). Version 1.2. MEDiscuss Clinical Decision Support System. Published 2026. Accessed . https://mediscuss.org/cdss/renal-staging. doi:10.5281/zenodo.22401636
Vancouver Style:Umakanth S. AKI and CKD Staging Pathway (KDIGO) [Internet]. Version 1.2. MEDiscuss.org; 2026 [cited ]. Available from: https://mediscuss.org/cdss/renal-staging. doi:10.5281/zenodo.22401636
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Category Risk Scores & Diagnostic PathwaysPathway
Specialties Nephrology