CST3 and chronic kidney disease: Studies of bias (mean difference from reference method) usually overestimated GFR compared with the reference when using MDRD (range −1.0 to +3.5) or CKD-EPI (range −0.23 to +4.4) and underestimated when using cystatin C based equations (range −5.7 to −1.2) [38, 42–44].