Importantly, around the threshold for CKD diagnosis (GFR 45–74 ml/min/1.73 m2), cystatin C testing will also re‐classify a proportion of older adults with eGFRcys or eGFRcr‐cys >60 ml/min/1.73 m2 as lower risk, allowing direction of risk reduction strategies and specialty care resources to those at greatest risk for CKD complications (Figure 1). This evidence concerns the gene CST3 and chronic kidney disease.