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NCLEX-RN Fluid & Electrolyte
Imbalances Questions And Well Graded
Solutions With Rationales Updated
2026-2027
1. A client with heart failure has a serum potassium of 3.2 mEq/L. Which assessment
finding does the nurse expect?
A) Peaked T waves
B) Flat T waves and prominent U waves
C) Prolonged PR interval
D) Widened QRS complex
Correct Answer: B
Rationale: Hypokalemia (K <3.5 mEq/L) causes flat T waves and prominent U
waves on ECG. Peaked T waves (A) are seen in hyperkalemia. Prolonged PR
interval (C) and widened QRS (D) are seen in severe hyperkalemia.
2. A client with chronic kidney disease has a serum potassium of 6.8 mEq/L. Which ECG
change does the nurse expect?
A) Flat T waves
B) Prominent U waves
C) Peaked T waves
D) Prolonged QT interval
Correct Answer: C
Rationale: Hyperkalemia (K >5.0 mEq/L) causes peaked, tall, tented T waves on
ECG. Flat T waves (A) and prominent U waves (B) are seen in hypokalemia.
Prolonged QT interval (D) is seen in hypocalcemia.
3. A client with prolonged vomiting has a serum sodium of 125 mEq/L. Which
assessment finding does the nurse expect?
A) Thirst
B) Dry mucous membranes
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C) Confusion and lethargy
D) Increased urine output
Correct Answer: C
Rationale: Hyponatremia (Na <135 mEq/L) causes cerebral edema leading to
confusion, lethargy, and seizures. Thirst (A), dry mucous membranes (B), and
increased urine output (D) are signs of hypernatremia.
4. A client with diabetes insipidus has a serum sodium of 155 mEq/L. Which assessment
finding does the nurse expect?
A) Confusion
B) Muscle cramps
C) Thirst and dry mucous membranes
D) All of the above
Correct Answer: D
Rationale: Hypernatremia (Na >145 mEq/L) causes thirst, dry mucous
membranes (C), confusion (A), and muscle cramps (B). All are expected findings.
The priority is to correct the sodium slowly.
5. A client receiving IV furosemide has a serum potassium of 3.0 mEq/L. Which
intervention should the nurse implement?
A) Administer IV potassium chloride
B) Assess for muscle weakness and ECG changes
C) Increase the IV fluid rate
D) Notify the healthcare provider immediately
Correct Answer: B
Rationale: The nurse should first assess for signs of hypokalemia including
muscle weakness and ECG changes (B). IV potassium (A) may be prescribed but
assessment is first. Notifying the provider (D) occurs after assessment.
6. A client with renal failure has a serum calcium of 6.5 mg/dL. Which assessment
finding does the nurse expect?
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A) Positive Chvostek's sign
B) Positive Trousseau's sign
C) Numbness and tingling around the mouth
D) All of the above
Correct Answer: D
Rationale: Hypocalcemia (Ca <8.5 mg/dL) causes Chvostek's sign (A),
Trousseau's sign (B), and perioral numbness (C). All are expected findings. The
nurse should monitor for laryngospasm and seizures.
7. A client with hyperparathyroidism has a serum calcium of 12.5 mg/dL. Which
assessment finding does the nurse expect?
A) Muscle cramps
B) Positive Chvostek's sign
C) Bone pain and kidney stones
D) Perioral numbness
Correct Answer: C
Rationale: Hypercalcemia (Ca >10.5 mg/dL) causes bone pain, kidney stones,
and constipation. Muscle cramps (A), Chvostek's sign (B), and perioral
numbness (D) are signs of hypocalcemia.
8. A client with alcoholism has a serum magnesium of 1.2 mEq/L. Which assessment
finding does the nurse expect?
A) Tachycardia
B) Hypertension
C) Tremors and seizures
D) All of the above
Correct Answer: D
Rationale: Hypomagnesemia (Mg <1.5 mEq/L) causes tremors, seizures (C),
tachycardia (A), and hypertension (B). All are expected findings. The nurse
should monitor for cardiac dysrhythmias.
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9. A client with acute kidney injury has a serum phosphorus of 5.5 mg/dL. Which
assessment finding does the nurse expect?
A) Hypocalcemia
B) Hypercalcemia
C) Hyponatremia
D) Hypernatremia
Correct Answer: A
Rationale: Hyperphosphatemia (Phos >4.5 mg/dL) binds with calcium, causing
hypocalcemia (A). The nurse should monitor for signs of hypocalcemia
including Chvostek's and Trousseau's signs.
10. A client with heart failure has a serum sodium of 130 mEq/L. Which intervention
should the nurse implement?
A) Restrict oral fluids
B) Administer IV normal saline
C) Encourage increased fluid intake
D) Administer hypertonic saline
Correct Answer: A
Rationale: Hyponatremia in heart failure is often due to fluid overload
(dilutional hyponatremia). Fluid restriction (A) is the appropriate intervention.
IV normal saline (B) would worsen fluid overload. Hypertonic saline (D) is used
in severe symptomatic hyponatremia.
11. A client with diabetic ketoacidosis has a serum potassium of 5.8 mEq/L despite total
body potassium depletion. Which explanation is correct?
A) The client has true hyperkalemia
B) Potassium shifted from intracellular to extracellular space
C) The client has renal failure
D) The client received too much potassium
Correct Answer: B
Rationale: In DKA, acidosis causes potassium to shift from intracellular to
extracellular space (B), resulting in a falsely elevated serum potassium despite
NCLEX-RN Fluid & Electrolyte
Imbalances Questions And Well Graded
Solutions With Rationales Updated
2026-2027
1. A client with heart failure has a serum potassium of 3.2 mEq/L. Which assessment
finding does the nurse expect?
A) Peaked T waves
B) Flat T waves and prominent U waves
C) Prolonged PR interval
D) Widened QRS complex
Correct Answer: B
Rationale: Hypokalemia (K <3.5 mEq/L) causes flat T waves and prominent U
waves on ECG. Peaked T waves (A) are seen in hyperkalemia. Prolonged PR
interval (C) and widened QRS (D) are seen in severe hyperkalemia.
2. A client with chronic kidney disease has a serum potassium of 6.8 mEq/L. Which ECG
change does the nurse expect?
A) Flat T waves
B) Prominent U waves
C) Peaked T waves
D) Prolonged QT interval
Correct Answer: C
Rationale: Hyperkalemia (K >5.0 mEq/L) causes peaked, tall, tented T waves on
ECG. Flat T waves (A) and prominent U waves (B) are seen in hypokalemia.
Prolonged QT interval (D) is seen in hypocalcemia.
3. A client with prolonged vomiting has a serum sodium of 125 mEq/L. Which
assessment finding does the nurse expect?
A) Thirst
B) Dry mucous membranes
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C) Confusion and lethargy
D) Increased urine output
Correct Answer: C
Rationale: Hyponatremia (Na <135 mEq/L) causes cerebral edema leading to
confusion, lethargy, and seizures. Thirst (A), dry mucous membranes (B), and
increased urine output (D) are signs of hypernatremia.
4. A client with diabetes insipidus has a serum sodium of 155 mEq/L. Which assessment
finding does the nurse expect?
A) Confusion
B) Muscle cramps
C) Thirst and dry mucous membranes
D) All of the above
Correct Answer: D
Rationale: Hypernatremia (Na >145 mEq/L) causes thirst, dry mucous
membranes (C), confusion (A), and muscle cramps (B). All are expected findings.
The priority is to correct the sodium slowly.
5. A client receiving IV furosemide has a serum potassium of 3.0 mEq/L. Which
intervention should the nurse implement?
A) Administer IV potassium chloride
B) Assess for muscle weakness and ECG changes
C) Increase the IV fluid rate
D) Notify the healthcare provider immediately
Correct Answer: B
Rationale: The nurse should first assess for signs of hypokalemia including
muscle weakness and ECG changes (B). IV potassium (A) may be prescribed but
assessment is first. Notifying the provider (D) occurs after assessment.
6. A client with renal failure has a serum calcium of 6.5 mg/dL. Which assessment
finding does the nurse expect?
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A) Positive Chvostek's sign
B) Positive Trousseau's sign
C) Numbness and tingling around the mouth
D) All of the above
Correct Answer: D
Rationale: Hypocalcemia (Ca <8.5 mg/dL) causes Chvostek's sign (A),
Trousseau's sign (B), and perioral numbness (C). All are expected findings. The
nurse should monitor for laryngospasm and seizures.
7. A client with hyperparathyroidism has a serum calcium of 12.5 mg/dL. Which
assessment finding does the nurse expect?
A) Muscle cramps
B) Positive Chvostek's sign
C) Bone pain and kidney stones
D) Perioral numbness
Correct Answer: C
Rationale: Hypercalcemia (Ca >10.5 mg/dL) causes bone pain, kidney stones,
and constipation. Muscle cramps (A), Chvostek's sign (B), and perioral
numbness (D) are signs of hypocalcemia.
8. A client with alcoholism has a serum magnesium of 1.2 mEq/L. Which assessment
finding does the nurse expect?
A) Tachycardia
B) Hypertension
C) Tremors and seizures
D) All of the above
Correct Answer: D
Rationale: Hypomagnesemia (Mg <1.5 mEq/L) causes tremors, seizures (C),
tachycardia (A), and hypertension (B). All are expected findings. The nurse
should monitor for cardiac dysrhythmias.
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9. A client with acute kidney injury has a serum phosphorus of 5.5 mg/dL. Which
assessment finding does the nurse expect?
A) Hypocalcemia
B) Hypercalcemia
C) Hyponatremia
D) Hypernatremia
Correct Answer: A
Rationale: Hyperphosphatemia (Phos >4.5 mg/dL) binds with calcium, causing
hypocalcemia (A). The nurse should monitor for signs of hypocalcemia
including Chvostek's and Trousseau's signs.
10. A client with heart failure has a serum sodium of 130 mEq/L. Which intervention
should the nurse implement?
A) Restrict oral fluids
B) Administer IV normal saline
C) Encourage increased fluid intake
D) Administer hypertonic saline
Correct Answer: A
Rationale: Hyponatremia in heart failure is often due to fluid overload
(dilutional hyponatremia). Fluid restriction (A) is the appropriate intervention.
IV normal saline (B) would worsen fluid overload. Hypertonic saline (D) is used
in severe symptomatic hyponatremia.
11. A client with diabetic ketoacidosis has a serum potassium of 5.8 mEq/L despite total
body potassium depletion. Which explanation is correct?
A) The client has true hyperkalemia
B) Potassium shifted from intracellular to extracellular space
C) The client has renal failure
D) The client received too much potassium
Correct Answer: B
Rationale: In DKA, acidosis causes potassium to shift from intracellular to
extracellular space (B), resulting in a falsely elevated serum potassium despite
