Cells

RBCs: think glomerular disease if "dysmorphic"

Eosinophils: think drug induced or allergic interstitial nephritis (do not see in NSAID-induced renal disease)

Wright and Hansel stains detect eosinophils in the urine.

Sterile Pyuria: partially treated/ TB, prostatitis, analgesic abuse nephropathy

• Persistent WBC on UA with negative culture can be TB.

Casts

RBC: Glomerulonephritis

WBC: Pyelonephritis

Eosinophil: Acute (allergic) interstitial nephritis

renal tubular cell casts : interstitial inflammation

Acellular casts

Hyaline casts: non-specific, maybe normal (Dehydration concentrates the urine and the normal Tamm-Horsfall protein precipitates or concentrates into a cast)

Granular "muddy-brown" : ATN

Broad, waxy casts: CKD

Crystals

Urine specific gravity correlates to urine osmolality. (High UOsm = high specific gravity)

Fractional Excretion of Na:

Pre-renal azotemia: FENa <1