Mrs. Cherry, 32, in the emergency department with abdominal cramps, diarrhea, vomiting, and abdominal distention. The physician orders lab tests. Which result will the nurse be most interested in?

• A. Electrolytes
• B. White blood cell count
• C. Blood urea nitrogen
• D. Glucose

Answer: (A)

In acute GI losses like vomiting and diarrhea, the immediate concern is fluid and electrolyte balance. Electrolytes give a direct read on how much fluid has shifted and what acid–base changes are happening, which is crucial for guiding treatment and preventing serious problems such as dangerous heart rhythms and muscle weakness. The nurse will focus on electrolyte levels—sodium, potassium, chloride, and bicarbonate—to assess dehydration severity and the body's acid-base status, so IV fluids and electrolyte replacements can be tailored appropriately. Potassium, in particular, is often disrupted with GI losses and can lead to critical issues if not corrected. Chloride and bicarbonate levels help distinguish whether the disturbance is more from vomiting (often causing metabolic alkalosis) or diarrhea (often causing metabolic acidosis). While other labs like white blood cell count, BUN, or glucose can provide useful context, they don’t as directly indicate the patient’s current fluid and electrolyte status.