CST3 and hyperinsulinemic hypoglycemia, familial, 4: Indeed, when we analyzed the influence of MBL deficiency on the cystatin C course after CM exposure we observed a remarkable association: As compared to patients with MBL levels >500 ng/mL subjects with MBL deficiency were almost two-times less likely to develop a cystatin C increase ≥10% after administration of CM, a cut-off that has recently been proposed as an independent diagnostic and prognostic tool with respect to the occurrence of CIN and future adverse events [20].