1
NCLEX 2025 Lab Values Mastery | Color-Coded Chart
+ 200 Practice Questions with Detailed Rationales
1.
A patient’s serum potassium is 6.2 mEq/L. Which action should the nurse take
first?
A. Administer oral potassium supplement
B. Prepare the patient for dialysis
C. Place the patient on cardiac monitoring
D. Encourage a high-potassium diet
Answer: C. Place the patient on cardiac monitoring
Rationale: Hyperkalemia can cause life-threatening cardiac arrhythmias such as
, 2
ventricular fibrillation. The immediate priority is to place the patient on continuous
cardiac monitoring to detect and treat dysrhythmias early. Dialysis or other
interventions may follow, but first, ensure the patient’s heart rhythm is monitored.
2.
Which lab value requires immediate intervention?
A. Sodium 140 mEq/L
B. Calcium 6.5 mg/dL
C. Hemoglobin 12 g/dL
D. Magnesium 2 mEq/L
Answer: B. Calcium 6.5 mg/dL
Rationale: Normal calcium is 8.5–10.5 mg/dL. A calcium level of 6.5 indicates
severe hypocalcemia, which can cause tetany, seizures, and life-threatening
laryngeal spasms. This requires rapid IV calcium replacement and cardiac
monitoring.
3.
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A client with chronic kidney disease has a BUN of 55 mg/dL. Which
interpretation is correct?
A. Indicates dehydration or renal dysfunction
B. Indicates liver failure
C. This is within normal limits
D. Suggests hyperthyroidism
Answer: A. Indicates dehydration or renal dysfunction
Rationale: Normal BUN is 7–20 mg/dL. A level of 55 suggests impaired renal
clearance or severe dehydration. Elevated BUN alone is nonspecific, but in kidney
disease, it reflects decreased renal excretion of nitrogenous waste.
4.
A postoperative client has a WBC count of 15,000/mm³. Which action is most
appropriate?
A. Continue routine care
B. Assess the surgical site and vital signs
C. Administer prophylactic anticoagulants
D. Place the client in isolation
, 4
Answer: B. Assess the surgical site and vital signs
Rationale: Normal WBC is 4,000–11,000/mm³. A level of 15,000 indicates
possible infection or inflammatory response. The nurse should assess for fever,
drainage, or erythema at the surgical site before notifying the provider.
5.
Which INR value is therapeutic for a client on warfarin for atrial fibrillation?
A. 1.0
B. 1.5
C. 2.5
D. 5.0
Answer: C. 2.5
Rationale: The therapeutic INR for atrial fibrillation is typically 2.0–3.0. A value
of 2.5 is appropriate and indicates adequate anticoagulation. Values above 3.5
increase bleeding risk, and 1.0 is subtherapeutic.
6.
NCLEX 2025 Lab Values Mastery | Color-Coded Chart
+ 200 Practice Questions with Detailed Rationales
1.
A patient’s serum potassium is 6.2 mEq/L. Which action should the nurse take
first?
A. Administer oral potassium supplement
B. Prepare the patient for dialysis
C. Place the patient on cardiac monitoring
D. Encourage a high-potassium diet
Answer: C. Place the patient on cardiac monitoring
Rationale: Hyperkalemia can cause life-threatening cardiac arrhythmias such as
, 2
ventricular fibrillation. The immediate priority is to place the patient on continuous
cardiac monitoring to detect and treat dysrhythmias early. Dialysis or other
interventions may follow, but first, ensure the patient’s heart rhythm is monitored.
2.
Which lab value requires immediate intervention?
A. Sodium 140 mEq/L
B. Calcium 6.5 mg/dL
C. Hemoglobin 12 g/dL
D. Magnesium 2 mEq/L
Answer: B. Calcium 6.5 mg/dL
Rationale: Normal calcium is 8.5–10.5 mg/dL. A calcium level of 6.5 indicates
severe hypocalcemia, which can cause tetany, seizures, and life-threatening
laryngeal spasms. This requires rapid IV calcium replacement and cardiac
monitoring.
3.
, 3
A client with chronic kidney disease has a BUN of 55 mg/dL. Which
interpretation is correct?
A. Indicates dehydration or renal dysfunction
B. Indicates liver failure
C. This is within normal limits
D. Suggests hyperthyroidism
Answer: A. Indicates dehydration or renal dysfunction
Rationale: Normal BUN is 7–20 mg/dL. A level of 55 suggests impaired renal
clearance or severe dehydration. Elevated BUN alone is nonspecific, but in kidney
disease, it reflects decreased renal excretion of nitrogenous waste.
4.
A postoperative client has a WBC count of 15,000/mm³. Which action is most
appropriate?
A. Continue routine care
B. Assess the surgical site and vital signs
C. Administer prophylactic anticoagulants
D. Place the client in isolation
, 4
Answer: B. Assess the surgical site and vital signs
Rationale: Normal WBC is 4,000–11,000/mm³. A level of 15,000 indicates
possible infection or inflammatory response. The nurse should assess for fever,
drainage, or erythema at the surgical site before notifying the provider.
5.
Which INR value is therapeutic for a client on warfarin for atrial fibrillation?
A. 1.0
B. 1.5
C. 2.5
D. 5.0
Answer: C. 2.5
Rationale: The therapeutic INR for atrial fibrillation is typically 2.0–3.0. A value
of 2.5 is appropriate and indicates adequate anticoagulation. Values above 3.5
increase bleeding risk, and 1.0 is subtherapeutic.
6.
