The nurse is analyzing the diagnostic results of a female patient who has nausea, vomiting, and was admitted for an exacerbation of ulcerative colitis with bloody, purulent stool (See the table below). Which of the following orders does the nurse implement first? Diagnostic Test Result Reference Range Serum White Blood Cell (WBC) count 18.500/mm3 4,500-10,000/mm3 Serum Potassium 3.4 mEq/L 3.5-5.0 mEq/L Serum Sodium 136 mEq/L 135-145 mEq/L