Urinalysis
Urine microscopy
Microscopic exam of urine sediment — casts, crystals, cells.
Sample
Fresh spun urine
Biology
What it measures
Centrifuged sediment examined at 400×.
Multi-marker patterns
Pattern recognition
RBC casts
Pathognomonic for glomerular bleeding — glomerulonephritis until proven otherwise.
WBC casts
Pyelonephritis or interstitial nephritis (often eosinophiluria with the latter).
Muddy-brown granular casts
Acute tubular necrosis.
Waxy / broad casts
Chronic kidney disease with dilated nephrons.
Hyaline casts
Nonspecific — dehydration, exercise, normal urine.
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