Table 1.

Definition of CKDu

Suspected CKDu

1. eGFR<60 mL/min/1.73m2.

2. and or albuminuria>30mg/g

3. and or proteinuria>150 mg/g

All Any of the above in the absence of HT, DM, AKI.

Exclusion criteria; proteinuria >2g/g excludes the diagnosis

Probable CKDu

1. Fulfill the criteria of “Suspected CKDu”

2. Hypokalemia and/or hyperuricemia

3. 1 AND 2 in the absence of autoimmune disease, glomerular disease, congenital kidney disease, obstructive kidney disease

Confirmed after repeat assessment at week 12

Confirmed CKDu

All of the above-mentioned criteria for probable CKDu

AND histopathological features consistent with CKDu on kidney biopsy (pyelonephritis and interstitial nephritis caused by specific etiology should be excluded from the definition).

* In those cases where kidney biopsy is not possible, CKDu can be clinically confirmed with the above mentioned criteria for probable CKDu

Note: Adapted from Anupama YJ, Sankarasubbaiyan S, Taduri G. Chronic kidney disease of unknown etiology: case definition for India – a perspective. Indian J Nephrol. 2020.28