Electrolytes Question #42


A client has been vomiting and has had numerous episodes of diarrhea. Which laboratory test should the nurse monitor?


  1. Serum calcium.
    • Rationale:
  2. Serum phosphorus.
    • Rationale:
  3. Serum potassium.
    • Rationale:
  4. Serum sodium.
    • Rationale:



The correct answer is C. A large amount of potassium can be lost through emesis and diarrhea. The serum potassium level should be monitored to detect adverse effects of hypokalemia to include cardiac dysrhythmias. Calcium, phosphorus, and sodium levels are not depleted with emesis and diarrhea.

NCLEX TIP: Using critical thinking is recommended when reading priority questions. Recognizing key words in the answer choices will allow you to know how to choose the correct answer for the question. Go through each answer choice and decide is it: Maslow’s hierarchy, safety-related, or following the nursing process (ADPIE). Never complete a nursing action that is outside the scope of practice.

Learning Outcomes

Test Taking Tip

Video Rationale