CST3 and chronic kidney disease: Recalibration of the cystatin C containing equations with Siemens data reduced bias and increased P30: for example, P30 for CKD-EPIcystatin changed from 72.5 (95% CI 69.8 to 75.0) to 89.5 (87.6 to 91.2) when recalibrated values were used.