KL and acute kidney injury: When contrasting these findings with cardiac surgery patients who did not develop AKI, a statistically significant difference was observed only with the ELISA kit from Shanghai Sunred Biological Technology Co., Ltd. (Shanghai, China), and not with the gold standard kit by IBL International (Human soluble a-Klotho Assay Kit–IBL, Immuno-Biological Laboratories Co., Ltd., Hamburg, Germany) [26].