Which statement best describes the purpose of ESRD-specific tests BUN, Creatinine, and URR?

• A. They measure liver function
• B. They indicate adequacy of renal replacement therapy
• C. They measure blood viscosity
• D. They assess bone density

Answer: (B)

These tests focus on how effectively dialysis is removing waste from the blood, which is the essence of assessing renal replacement therapy. In ESRD, the kidneys can’t clear waste products like urea and creatinine, so dialysis must do this work. Measuring BUN and creatinine levels before and after a dialysis session shows how much waste the treatment clears from the bloodstream. The Urea Reduction Ratio takes that drop in BUN and expresses it as a percentage, giving a quick, practical gauge of the session’s effectiveness. Together, these measures guide adjustments to the dialysis prescription to ensure the patient receives adequate treatment.

They aren’t about liver function, blood viscosity, or bone density—those require different tests and assessments.