Urinalysis & Urine Microscopy: The Cheapest, Most Underread Lab in Medicine
Urinalysis & Urine Microscopy: The Cheapest, Most Underread Lab in Medicine Casts are the single most underappreciated finding in all of lab medicine. If you learn nothing else from this post, learn the casts. The urinalysis costs almost nothing, requires no special equipment, and can diagnose everything from UTI to lupus nephritis to multiple myeloma. Yet most providers look at the leukocyte esterase and nitrites, maybe the protein, and close the chart. The microscopy section? Ignored. The casts? Never read. The dipstick subtleties? Missed entirely. Let's fix that, one component at a time. Part 1: The Dipstick Specific Gravity Reflects urine concentration (1.001–1.030). Why it matters: a "trace" protein on a highly concentrated specimen (SG 1.030) may actually represent significant proteinuria. Conversely, 1+ protein on a dilute specimen (SG 1.005) is worrisome. Always interpret protein in the context of concentration. pH Normal range 4.5–8.0 (average ~6.0). Alkal...