As the risk of death increases with diagnosis of CKD associated with an estimated GFR below 60 mL/min/1.73 m2 [41], KDIGO recommends using serum creatinine-based GFR estimation for initial assessment of GFR and to use additional tests (such as cystatin C or clearance method) for confirmatory testing once eGFR is <60 mL/min/1.73 m2. Here, CST3 is linked to chronic kidney disease.