CKD Stage Classification Calculator

No. In the KDIGO 2012 system this calculator implements, CKD Stage (G1 through G5) is determined entirely by eGFR, while albuminuria category (A1 through A3) is reported as a separate, independent axis based on UACR. The two axes are combined only in the KDIGO Risk Level output -- the heat map -- not in the Stage number itself, so changing UACR alone never moves the CKD Stage.

Yes, and this is a deliberate feature of the KDIGO staging system, not an inconsistency. CKD Stage reflects GFR category alone, while KDIGO Risk Level reads a heat map that combines GFR category with albuminuria category. Two patients with identical eGFR (and therefore identical CKD Stage) can land in different risk tiers if their UACR differs -- higher albuminuria pushes the same GFR category into a higher risk color band.

In the published KDIGO heat map, the G3b/A2 combination (eGFR 30-44 with a UACR of 30-300 mg/g) is classified red, or very-high risk -- one tier higher than the same UACR at the milder G3a stage (eGFR 45-59), which is orange/high risk. This reflects that moderately increased albuminuria carries disproportionately more progression risk once GFR has already dropped into the G3b range, not a simple linear scaling of risk with GFR alone.

No. It's a simplified estimate built from KDIGO's general finding that CKD progression risk rises with both a lower GFR category and a higher albuminuria category, not a separately validated prediction equation like the Kidney Failure Risk Equation. Treat it as a rough, directionally-consistent estimate rather than a precise clinical prediction tool.