- Choose Conventional (mg/g) or SI (mg/mmol) units to match your lab report. Switching units clears the protein fields.
- Enter the UACR (preferred) and/or the PCR. If only PCR is available, the tool estimates the albuminuria category from it; UACR takes precedence when both are entered.
- Enter the most recent eGFR to set the GFR category, and indicate whether the patient is already on RAAS blockade (ACE inhibitor or ARB).
- Results update live: the KDIGO albuminuria category (A1–A3), GFR category (G1–G5), the combined risk classification, the recommended monitoring frequency, and a plain-language interpretation with management prompts.
All computation runs in your browser; no values are stored or transmitted.
When to Use
Use this tool to classify proteinuria in any adult being screened for or living with chronic kidney disease. It converts a urine albumin-to-creatinine ratio (UACR) or protein-to-creatinine ratio (PCR) into the KDIGO albuminuria category (A1–A3), then intersects that category with the eGFR-derived GFR category (G1–G5) to give the combined KDIGO risk classification — the "heat map" cell that determines how often to monitor and how aggressively to treat.
Appropriate population
Adults with diabetes, hypertension, established CKD, or other risk factors who have a spot UACR (preferred) or PCR plus a recent eGFR. Most useful when staging newly detected CKD, deciding monitoring intervals, or assessing whether RAAS blockade and SGLT2-inhibitor therapy are indicated for proteinuria reduction.
When NOT to rely on it
A single elevated UACR does not diagnose CKD — KDIGO requires albuminuria be confirmed on at least 2 of 3 samples over ≥3 months. Transient proteinuria from fever, vigorous exercise, urinary tract infection, menstrual contamination, decompensated heart failure, or marked hyperglycemia inflates the ratio. Very low or very high urine creatinine (extremes of muscle mass) distorts the ratio. Do not use in acute kidney injury, where staging categories do not apply.
Pearls & Pitfalls
Albuminuria is a treatment target, not just a stage
Lowering albuminuria with RAAS blockade and SGLT2 inhibitors slows GFR decline independently of blood-pressure effect. A 30% or greater reduction in UACR is a recognized surrogate for renoprotection — recheck the ratio after starting or up-titrating therapy.
Prefer UACR and confirm it
Use a first-morning or random spot UACR rather than dipstick, which is insensitive at the A2 range and concentration-dependent. Confirm a positive result on 2 of 3 samples over ≥3 months before labeling persistent albuminuria, and avoid testing during fever, UTI, heavy exercise, or menstruation.
Pitfalls
(1) The spot ratio is distorted by urine creatinine extremes — very muscular patients overstate and cachectic/elderly patients understate true excretion. (2) PCR underestimates the albuminuria category when tubular or overflow (e.g. light-chain) proteins dominate; UACR and PCR diverge in those settings. (3) The G×A cell classifies risk but does not identify cause — always pursue the underlying diagnosis. (4) Nephrotic-range proteinuria (UACR > 2200 mg/g or PCR > ~3500 mg/g) warrants prompt nephrology referral regardless of GFR.
Why Use It
Albuminuria is an independent, graded predictor of CKD progression, end-stage kidney disease, cardiovascular events, and all-cause mortality — risk that compounds with declining GFR. KDIGO's two-dimensional G×A staging captures this synergy far better than eGFR alone: a patient with preserved GFR but A3 albuminuria can carry higher absolute risk than one with reduced GFR and A1. Standardizing the UACR/PCR result into the correct category ensures monitoring frequency, RAAS blockade, and SGLT2-inhibitor decisions rest on the validated risk cell rather than a raw number.
Proteinuria Calculator — UACR Staging, PCR & CKD Risk Classification
Enter your urine protein or albumin results to determine your KDIGO albuminuria category, cross-reference it with your eGFR stage, and understand what your combined risk classification means for monitoring and treatment.
⚕ UACR categories: A1 <30 mg/g (normal/mildly increased), A2 30–300 mg/g (moderately increased), A3 >300 mg/g (severely increased). GFR categories: G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15. Combined KDIGO risk classification uses the intersecting cell of G and A categories (green/yellow/orange/red heat map). PCR ≈ UACR × 1.1–1.3 correction for non-albumin proteins. UACR should be confirmed on at least 2 of 3 samples before diagnosing CKD.
Next Steps
Use the result to support — not replace — clinical judgment.
- Interpret the value against the targets shown in the calculator and the Evidence section below, in the context of the full clinical picture.
- Trend serial measurements rather than acting on a single result; confirm abnormal or unexpected values before changing management.
- Apply the relevant KDIGO / specialty-guideline threshold and document the indication.
- Escalate or refer to nephrology when results are out of range, rapidly changing, or discordant with the clinical picture — and discuss the implications with the patient.
Evidence & References
Formula & Equations
| Quantity | Definition / Equation |
|---|---|
| UACR (mg/g) | Urine albumin (mg/L) ÷ urine creatinine (g/L), from a spot sample |
| UACR unit conversion | UACR (mg/g) = UACR (mg/mmol) ÷ 0.1130; i.e. 1 mg/mmol ≈ 8.85 mg/g |
| PCR → albuminuria estimate | Effective UACR ≈ PCR ÷ 1.2 when only PCR is reported |
| Estimated 24-h urine protein | ≈ UACR (mg/g) ÷ 1000 ≈ g/day (spot ratio approximates daily excretion) |
KDIGO category thresholds
| Category | Range |
|---|---|
| A1 — Normal to mildly increased | UACR < 30 mg/g (< 3 mg/mmol) |
| A2 — Moderately increased | UACR 30–300 mg/g (3–30 mg/mmol) |
| A3 — Severely increased | UACR > 300 mg/g (> 30 mg/mmol) |
| GFR categories | G1 ≥90 · G2 60–89 · G3a 45–59 · G3b 30–44 · G4 15–29 · G5 <15 mL/min/1.73 m² |
| Combined risk | Intersecting G×A cell of the KDIGO heat map: low (green), moderately increased (yellow), high (orange), very high (red) |
UACR is preferred over PCR because albumin is the dominant pathological protein in most CKD and the albumin assay is more sensitive at low levels. The G×A heat map is the KDIGO "Cause-GFR-Albuminuria" (CGA) classification; cause should be specified separately.
Evidence & References
The albuminuria categories (A1–A3) and the combined GFR–albuminuria risk heat map are defined by the KDIGO Clinical Practice Guideline for the Evaluation and Management of CKD (2012, updated 2024). The two-dimensional staging arose from the KDIGO controversies conference synthesis of the CKD Prognosis Consortium meta-analyses, which demonstrated that albuminuria predicts mortality and ESKD independently of, and multiplicatively with, eGFR.
- 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.
- Levey AS, de Jong PE, Coresh J, et al. The definition, classification, and prognosis of chronic kidney disease: a KDIGO Controversies Conference report. Kidney Int. 2011;80(1):17–28.
- 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.
