Cluster 113: creatinine serum uln times institutional concentration days prior equal levels Cluster 303: creatinine upper limit normal times institutional serum uln institution age Cluster 530: amylase lipase uln serum normal institutional days registration prior limits Cluster 820: potassium limits normal meq serum range institutional institution wnl supplementation Cluster 927: limits creatinine normal institutional upper serum uln times troponin days Cluster 1700: limits bilirubin normal upper total uln serum institutional times ast Cluster 1782: renal creatinine function uln serum adequate times defined normal mg