CKD Risk Heat Map Interpreter (KDIGO G and A)
CKD Risk Heat Map Interpreter (KDIGO G and A)
Place an eGFR and a urine albumin-creatinine ratio on the KDIGO chronic kidney disease heat map: the G category (G1 to G5), the A category (A1 to A3), the risk colour — low, moderately increased, high or very high — and how often KDIGO’s grid suggests checking eGFR and ACR. CKD itself needs the abnormality to persist for more than 3 months.
Where does this patient sit on the KDIGO heat map?
eGFR + ACR → G and A category, risk colour, monitoringA 66-year-old with type 2 diabetes: eGFR 52 mL/min/1.73 m² and ACR 45 mg/g, both confirmed on repeat over 4 months.
Two axes, one colour
A: A1 below 30 mg/g (3 mg/mmol) · A2 30–300 (3–30) · A3 above 300 (30)
Colour rises with both: green (low) → yellow (moderately increased) → orange (high) → red (very high)
- G category
- from the eGFR; see the CKD GFR stage calculator
- A category
- from the ACR; see the KDIGO albuminuria category calculator
- monitoring
- times per year for eGFR and ACR, from the KDIGO 2012 grid (Figure 17)
Worked example
A 66-year-old with type 2 diabetes: eGFR 52 mL/min/1.73 m² and ACR 45 mg/g, both confirmed on repeat over 4 months.
eGFR 52 is between 45 and 59 → G3a
ACR 45 mg/g is between 30 and 300 → A2
G3a A2 is orange on the KDIGO heat map → high risk
KDIGO 2012 grid: twice a year; persistent over 3 months, so this is CKD G3a A2
The KDIGO grid: risk colour and monitoring per year
| GFR category | A1 | A2 | A3 |
|---|---|---|---|
| G1 — eGFR 90 or more | Green · 1 if CKD | Yellow · 1 | Orange · 2 |
| G2 — eGFR 60–89 | Green · 1 if CKD | Yellow · 1 | Orange · 2 |
| G3a — eGFR 45–59 | Yellow · 1 | Orange · 2 | Red · 3 |
| G3b — eGFR 30–44 | Orange · 2 | Red · 3 | Red · 3 |
| G4 — eGFR 15–29 | Red · 3 | Red · 3 | Red · 4+ |
| G5 — eGFR below 15 (kidney failure) | Red · 4+ | Red · 4+ | Red · 4+ |
Why both numbers, and why 3 months
KDIGO classifies chronic kidney disease by cause, GFR category and albuminuria category, and its heat map crosses the last two. Each axis on its own is on the site already — the CKD GFR stage calculator gives G1 to G5 and the KDIGO albuminuria category calculator gives A1 to A3 — but the risk sits in the combination. At any eGFR, more albumin in the urine means more risk of kidney failure, cardiovascular events and death, and at any ACR, a lower eGFR does the same. So G3a with no albuminuria is yellow, while G1 with an ACR above 300 mg/g is orange: a normal eGFR does not make heavy albuminuria safe.
The grid needs persistence. KDIGO defines CKD as abnormalities of kidney structure or function present for more than 3 months, with implications for health. A single raised ACR, or an eGFR taken during an acute illness, cannot be placed on the grid; repeat it. And the green cells, G1 A1 and G2 A1, are not CKD at all unless another marker of kidney damage is present — haematuria, an abnormal scan or biopsy, a tubular disorder, or a transplant.
The numbers in the cells are how often to measure eGFR and ACR each year. This page prints the KDIGO 2012 grid because it is the version that could be verified. The 2024 guideline revised the grid, and it did so at least in G1 A3, which rose from twice to three times a year; the rest of the 2024 grid could not be confirmed, and several websites that label the 2012 numbers as 2024 are wrong in that cell. KDIGO 2024’s own practice point is simpler: measure albuminuria and GFR at least once a year in everyone with CKD, and more often in those at higher risk of progression. The ACR thresholds are a rounded pair — 30 mg/g with 3 mg/mmol, 300 mg/g with 30 mg/mmol — so each unit is tested against its own figure. This page supports clinical judgement and does not replace it.
Frequently asked questions
What do the colours on the KDIGO heat map mean?
Green is low risk (and not CKD without another marker of kidney damage), yellow moderately increased risk, orange high risk and red very high risk of kidney failure, cardiovascular events and death.
How long must an abnormal eGFR or ACR last to count as CKD?
More than 3 months. KDIGO defines CKD as abnormalities of kidney structure or function present for more than 3 months with implications for health.
How often should eGFR and ACR be checked?
KDIGO 2024 says at least once a year in everyone with CKD and more often at higher risk. The KDIGO 2012 grid gives one to four or more times a year by cell; KDIGO 2024 raised G1 A3 to three times a year.
Why is G1 A3 higher risk than G3a A1?
Because heavy albuminuria carries substantial risk even with a normal eGFR. On the heat map G1 A3 is orange (high risk) and G3a A1 is yellow (moderately increased).
Related calculators
References
- 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.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl. 2013;3(1):1–150. Figure 9 (prognosis by GFR and albuminuria category) and Figure 17 (frequency of monitoring).
- European Renal Best Practice. KDIGO 2024 clinical practice guideline for the evaluation and management of chronic kidney disease in children and adults: a commentary from the European Renal Best Practice (ERBP). Nephrol Dial Transplant. 2025;40(2):273.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.