Definitions:
CKD is persistently elevated serum Cr + reduced GFR
MC cause is T2DM and/or HTN
2 things to measure
Filtration (i.e. GFR)
Serum Creatinine (not elevated until ~%50 reduction in renal function)
Cystatin C
BUN
End product of protein metabolism
85% eliminated by kidneys, 15% by GI tract
Increases if renal elimination impaired (AKI, CKD), GI bleeding, high protein diet, severe liver disease
Increases earlier in chronic renal dysfunction than SCr
BUN:Cr Ratio:
Pre-renal: 20:1
Intrinsic renal: 10:1
Upper GIB: >30:1
Failed Protein Reabsorption
Proteinuria
Albuminuria
Cystatin C