Recommended tools	Details
1. General population sampling
Sampling methods	Describe: – sampling frame, i.e. source used to identify subjects – sample design, i.e. method of subject selection (e.g. age stratified, random)
Response	Report the response in percentages
2. Assessment of kidney function
Serum creatinine assay	Describe assay used, i.e. Jaffe or enzymatic
Albuminuria assay	Describe assay used, e.g. immunoassay and dipstick
IDMS calibration standardization	Describe if IDMS calibration standardization was used (yes/no)
CKD definition	Use of the same definition of CKD: CKD Stages 1–5: eGFR < 60mL/min/1.73 m² calculated by the CKD-EPI equation, and/or ACR > 30 mg/g. CKD Stages 3–5: eGFR < 60mL/min/1.73 m² calculated by CKD-EPI equation.
3. Presentation of results
CKD prevalence estimate	Report: – unadjusted and adjusted CKD prevalence (e.g. standardized to the EU27 population) – 95%CI
CKD prevalence estimate by strata	Report: – stratified by age groups: 20–44, 45–64, 65–74 and 75–84 years – stratified by diabetic, hypertension and obesity status
Serum creatinine determination	Indicate in tables and figures which studies use: – Jaffe or enzymatic assay – IDMS calibration standardization