NCLEX RN Practice Question # 929

NCLEX Examination.

Practice Question # 929.


nclex examination


Blood Urea Nitrogen (BUN), Uric Acid, Osmolality, Cystatin C Lab tests:

These tests are performed to measure kidney function, diagnose renal failure and kidney disease, and aid in kidney dialysis management.


  • Measure BUN as an index of renal function, the production and excretion of urea, and creatinine level. BUN should be checked in patients who are confused, disoriented, or convulsing.
  • Check uric acid levels to evaluate gout, renal failure, and the treatment of leukemia.
  • Assess urine osmolality to evaluate its concentration, hydration, SIADH, and diabetes insipidus.
  • Measure blood serum osmolality for toxic alcohol ingestion and to evaluate coma.
  • Measure serum cystatin C (low-molecular-weight proteinase inhibitor) to assess glomerular filtration in the elderly.
  • Note that creatinine clearance is usually performed with other tests of kidney function.

Reference Va l u e s Normal


Adults: 7–18 mg/dL or 2.5–6.4 mmol/L




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