In external validation studies, the KFRE has demonstrated high accuracy in predicting progression of CKD to kidney failure in diverse multinational settings, primary care populations, and children with CKD.2, 3, 4, 5, 6 The 4-variable version of the KFRE uses age, sex, eGFR, and urinary albumin-creatinine ratio (UACR); an 8-variable version exists that adds serum bicarbonate, albumin, calcium, and phosphorus levels. Here, ALB is linked to chronic kidney disease.