Nephrology

KDIGO Risk Matrix (GFR and Albuminuria Categories)

CKD progression risk category (G + A)

Primary source: KDIGO 2012 Clinical Practice Guideline for Evaluation and Management of CKD

Aleksandr A. Aulov, MD, internal medicine Last clinical review: April 28, 2026

Online calculation

Category G (by GFR)

Category A (ACR)

About this score

The KDIGO risk matrix is a two-dimensional classification of chronic kidney disease prognosis based on the combination of GFR and albuminuria. It was introduced by KDIGO in the 2012 guideline and updated in 2024. It replaces one-dimensional staging based on GFR alone, because albuminuria independently predicts CKD progression and cardiovascular events.

GFR categories: G1 (≥ 90), G2 (60–89), G3a (45–59), G3b (30–44), G4 (15–29), G5 (< 15). Albuminuria categories: A1 (< 30 mg/g), A2 (30–300 mg/g), A3 (> 300 mg/g). Combining the categories produces a color-coded matrix: green (low risk), yellow (moderate risk), orange (high risk), red (very high risk).

The matrix guides key decisions: monitoring frequency (2 times/year for orange, 4+ times/year for red), need for nephrology referral (orange — consider, red — mandatory), intensity of blood pressure control, and drug selection (SGLT2 inhibitors, finerenone). Major CKD guidelines use this matrix as the standard for risk stratification.

When to use

Established CKD — determining prognosis and management strategy.
Decision on nephrology referral.
Selecting the intensity of nephroprotective therapy (ACEi/ARB, SGLT2 inhibitors, finerenone).
Documenting the clinical rationale when reassessing follow-up care plans.

Clinical example

Case

65-year-old patient, type 2 diabetes for 15 years, CKD-EPI GFR 32 mL/min/1.73 m², urine albumin/creatinine ratio 450 mg/g.

Calculation

GFR 32 → G3b. Albuminuria 450 → A3. Combination G3b A3 → red zone of the matrix (very high risk).

Interpretation and management

Very high risk of CKD progression, kidney replacement therapy, and cardiovascular events. Management: mandatory nephrology follow-up, ACEi/ARB at the maximum tolerated dose with a target BP < 130/80, addition of an SGLT2 inhibitor (dapagliflozin is indicated at GFR ≥ 25), finerenone if albuminuria persists, glycemic control (HbA1c < 7% if hypoglycemia risk is low), statin, smoking cessation. Monitor GFR and albuminuria every 3 months. Prepare for kidney replacement therapy (vascular access, transplant discussion) as the patient approaches G4.

Limitations and cautions

The matrix does not account for the rate of GFR decline — rapid decline (> 5 mL/min/year) increases risk independent of the current category.
It does not account for CKD etiology — glomerulonephritis and diabetic nephropathy have different prognoses within the same matrix cell.
Albuminuria is a single point-in-time measurement — diagnosis requires 2–3 measurements over 3 months due to variability.
In patients on ACEi/ARB, albuminuria may be masked — this should be considered during initial risk stratification.

Frequently asked questions

Which urine sample should be used for albuminuria?

A morning sample with the albumin/creatinine ratio calculated. This is more convenient and comparable to a 24-hour collection. The alternative is a 24-hour urine collection (more accurate but less convenient).

At which matrix category is nephrology referral mandatory?

Red (very high risk) — mandatory. Orange (high risk) — recommended, especially in younger patients or with rapid progression. Yellow — follow-up with a primary care physician or endocrinologist.

What if GFR is normal but albuminuria is present?

G1 A2 or G1 A3 already meets the definition of CKD (a marker of kidney damage is present). Evaluation of the underlying cause (diabetes, hypertension, glomerulopathies) and nephroprotective therapy are needed.

Can the matrix category improve?

Yes, with adequate treatment (SGLT2 inhibitors, finerenone, ACEi/ARB, glycemic control), albuminuria decreases and the A category can shift down one level. GFR usually stabilizes; regression is uncommon but achievable.

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Aleksandr A. Aulov Physician, internal medicine, Sechenov School — independent medical education platform. Calculators are compiled from the original publications and current clinical guidelines. Interpretation thresholds follow the source study unless stated otherwise.

This calculator is intended for healthcare professionals. Do not use it for self-diagnosis or self-treatment. Management decisions are made by the treating clinician based on the full clinical picture of the individual patient.