NCLEX Fluids, Electrolytes & Lab Values Quiz

10 free NCLEX-style questions on electrolytes, fluid balance and interpreting lab values, each with a rationale.

NCLEX lab values questions study help – Dr. Blake NCLEX Review

NCLEX lab values questions: What You Need to Know

Looking for help with NCLEX lab values questions? You are in the right place. This guide gives nursing candidates across the USA and Canada clear, practical steps to prepare for the NCLEX with confidence.

Practice only: These are original practice questions written by Dr. Blake NCLEX Review to build clinical judgment. They are not actual NCLEX exam items and are not affiliated with NCSBN.

NCLEX Fluids, Electrolytes & Lab Values Quiz: 10 Questions with Rationales

Answer every question, then select Check My Answers to see your score and the rationale for each item.

Question 1

Choose one answer

Normal serum potassium range is:

A. 1.5–2.5 mEq/LB. 3.5–5.0 mEq/LC. 8.5–10.5 mEq/LD. 135–145 mEq/L

Correct answer: B
Normal potassium is 3.5–5.0 mEq/L. The 135–145 range is sodium; 8.5–10.5 mg/dL is calcium.

Question 2

Choose one answer

Which ECG change is associated with hyperkalemia?

A. Flattened T wavesB. Tall, peaked T wavesC. Prominent U wavesD. Shortened QT interval

Correct answer: B
Tall, peaked T waves are a hallmark of hyperkalemia. Flattened T waves and U waves suggest hypokalemia.

Question 3

Select all that apply

A client has a sodium of 118 mEq/L. The nurse anticipates which findings? Select all that apply.

A. ConfusionB. SeizuresC. Constipation as the priority concernD. HeadacheE. Muscle cramps

Correct answer: A, B, D, E
Severe hyponatremia causes neurologic symptoms: confusion, headache, seizures and muscle cramps due to cellular swelling.

Question 4

Choose one answer

Which sign indicates fluid volume deficit (dehydration)?

A. Bounding pulseB. Distended neck veinsC. Poor skin turgor and dry mucous membranesD. Crackles in the lungs

Correct answer: C
Fluid volume deficit causes poor skin turgor, dry mucous membranes, tachycardia and low blood pressure. The others suggest fluid overload.

Question 5

Select all that apply

A client with hypocalcemia may show which findings? Select all that apply.

A. Positive Chvostek’s signB. Positive Trousseau’s signC. ConstipationD. Numbness and tingling around the mouthE. Muscle twitching

Correct answer: A, B, D, E
Low calcium increases neuromuscular excitability: Chvostek’s and Trousseau’s signs, perioral tingling and twitching. Constipation is linked to hypercalcemia.

Question 6

Choose one answer

The normal range for serum sodium is:

A. 3.5–5.0 mEq/LB. 135–145 mEq/LC. 70–100 mg/dLD. 12–16 g/dL

Correct answer: B
Normal sodium is 135–145 mEq/L.

Question 7

Choose one answer

A client is receiving IV fluids and develops crackles, bounding pulse and shortness of breath. The nurse suspects:

A. Fluid volume deficitB. Fluid volume overloadC. HypokalemiaD. Metabolic acidosis

Correct answer: B
These are classic signs of fluid volume overload; the nurse should slow the infusion and notify the provider.

Question 8

Choose one answer

Which arterial blood gas indicates uncompensated respiratory acidosis?

A. pH 7.30, PaCO2 55, HCO3 24B. pH 7.50, PaCO2 30, HCO3 24C. pH 7.30, PaCO2 40, HCO3 18D. pH 7.48, PaCO2 40, HCO3 30

Correct answer: A
Low pH with a high PaCO2 and normal bicarbonate indicates uncompensated respiratory acidosis.

Question 9

Choose one answer

A normal fasting blood glucose is approximately:

A. 40–60 mg/dLB. 70–100 mg/dLC. 120–150 mg/dLD. 180–200 mg/dL

Correct answer: B
A normal fasting glucose is about 70–100 mg/dL.

Question 10

Choose one answer

A client with a magnesium of 1.0 mEq/L is at risk for which finding?

A. Hyperactive reflexes and possible seizuresB. Bradycardia and warm skinC. ConstipationD. Bounding pulses

Correct answer: A
Hypomagnesemia, like hypocalcemia, increases neuromuscular excitability, causing hyperactive reflexes and seizure risk.

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Study Tips for This Topic

Memorize normal ranges for potassium, sodium, calcium and glucose.
Link each electrolyte imbalance to its key signs and ECG changes.
Use ROME (Respiratory Opposite, Metabolic Equal) for ABGs.
Watch for fluid overload vs deficit clues.

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FAQ

What lab values should I memorize for the NCLEX?

Focus on electrolytes (K, Na, Ca, Mg), glucose, ABGs, coagulation (INR, aPTT) and complete blood count basics.

Are these real NCLEX questions?

No, they are original practice questions with rationales.