Regardless of age, it has been proven that cystatin C, when used together with creatinine to estimate eGFR, improves the strength of association of eGFR with adverse outcomes and is therefore a useful biomarker in improving the staging of CKD, especially in the cases where clinical suspicion of an inaccurate creatinine-based eGFR value exists (25, 26). The gene discussed is CST3; the disease is chronic kidney disease.