What is the purpose of a urinalysis sediment exam?

• A. To measure urine glucose concentration.
• B. To detect crystals, cells, casts, bacteria, and yeast, indicating disease.
• C. To quantify urine pH.
• D. To assess kidney filtration rate.

Answer: (B)

Think of the sediment exam as the microscopic look at the solid bits in urine. After concentrating the urine by spinning it, you inspect the sediment under a microscope to see crystals, cells (red or white blood cells), casts, bacteria, and yeast. The presence and type of these elements point to disease processes in the urinary tract or kidneys—stones (crystals), infection or inflammation (bacteria and white cells), bleeding or kidney damage (red cells), or tubular injury (casts). This is different from chemical tests that measure dissolved substances like glucose or pH or from calculations of kidney function; those assess chemistry or filtration rate, not microscopic debris. So the sediment exam’s purpose is to identify these microscopic constituents that indicate underlying disease.