Cluster 104: creatinine institutional normal levels clearance min ml upper limit patients 
Cluster 693: iuln creatinine serum registration days prior clearance min levels cockcroft 
Cluster 970: creatinine institutional normal limits clearance min levels ml patients gault 
Cluster 1550: creatinine clearance min ml uln calculated normal upper limit serum 
Cluster 1857: creatinine hour clearance min ml serum uln hr cr institutional 
Cluster 2478: scr creatinine ccr renal serum clearance min ml upper limit