Detection of CKD as a function of age and measurement of eGFR and urine ACR in the same patients. Relative proportions of ACR ≥ 30 mg/g, eGFR < 60 mL/min/1.73 m2, and both as positive screening tests for CKD in KEEP and NHANES 1999–2004. P < 0.001 for eGFR and ACR trend. ACR, albumin-creatinine ratio; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; KEEP, Kidney Early Evaluation Program; NHANES, National Health and Nutrition Examination Survey. Reproduced from McCullough et al17 with permission of the National Kidney Foundation.