<prompt> A with tumor lysis syndrome TLS is taking allopurinol Zyloprim. Which laboratory value should the nurse monitor to determine the effectiveness of the medication?Blood urea nitrogen BUNSerum phosphateSerum potassiumUric acid level  <response>: Allopurinol is used to decrease uric acid levels. BUN, potassium, and phosphate levels are also increased in TLS but are not affected by allopurinol therapy. 