Success! In Clinical Laboratory Science – Urinalysis and Body Fluids (UA/BF) Practice Test

Nephrotic-range protein loss causes lipiduria, which is reflected by lipid-filled tubular cells in urine known as oval fat bodies. When the kidneys lose large amounts of protein, the liver increases lipoprotein production, and lipids spill into the urine. The tubular cells that take up these lipids become engorged and appear as oval fat bodies under the microscope. This finding is particularly characteristic of nephrotic syndrome and helps distinguish it from other urinary findings.

Red blood cell casts point to glomerular bleeding or glomerulonephritis, waxy casts indicate chronic kidney disease, and bacteria in urine suggests infection; none specifically indicate the profound lipiduria seen with nephrotic-range protein loss.