LPN Interpreting Lab Values and Nursing Actions 5 — Questions and Answers
Question 1: A patient's serum lithium level is 2.2 mEq/L. What is the priority nursing action?
- Hold lithium, notify the provider, and monitor for toxicity signs (Correct answer)
- Administer the next scheduled dose to maintain therapeutic levels
- Encourage the patient to drink less fluid
- Document and continue to monitor every 8 hours
Correct answer: Hold lithium, notify the provider, and monitor for toxicity signs
Lithium toxicity occurs above 1.5 mEq/L; a level of 2.2 mEq/L is severely toxic and requires immediate intervention to prevent seizures and cardiac dysrhythmias.
Question 2: A patient's serum ammonia level is significantly elevated. Which condition does the LPN associate this with?
- Hepatic encephalopathy (Correct answer)
- Renal tubular acidosis
- Diabetic nephropathy
- Pulmonary hypertension
Correct answer: Hepatic encephalopathy
The liver normally converts ammonia to urea; in hepatic failure, ammonia accumulates and crosses the blood-brain barrier causing encephalopathy.
Question 3: A patient's CBC shows MCV of 115 fL and hypersegmented neutrophils. What nutritional deficiency is most likely?
- Vitamin B12 or folate deficiency (Correct answer)
- Iron deficiency
- Vitamin D deficiency
- Zinc deficiency
Correct answer: Vitamin B12 or folate deficiency
Macrocytosis (MCV >100 fL) with hypersegmented neutrophils is the hallmark of megaloblastic anemia caused by B12 or folate deficiency.
Question 4: A patient's serum creatinine rises from 0.9 mg/dL to 2.8 mg/dL over 48 hours post-contrast CT scan. What condition does this suggest?
- Contrast-induced nephropathy (acute kidney injury) (Correct answer)
- Normal response to IV contrast dye
- Pre-renal azotemia from dehydration only
- Chronic kidney disease exacerbation
Correct answer: Contrast-induced nephropathy (acute kidney injury)
A rapid rise in creatinine within 48-72 hours after contrast administration indicates contrast-induced acute kidney injury.
Question 5: A patient receiving TPN has a blood glucose of 310 mg/dL. What is the most appropriate nursing action?
- Notify the provider and anticipate an insulin order (Correct answer)
- Stop the TPN infusion immediately
- Slow the TPN rate by half without notifying the provider
- Recheck glucose in 4 hours with no immediate action
Correct answer: Notify the provider and anticipate an insulin order
Hyperglycemia during TPN requires provider notification to adjust insulin coverage; abruptly stopping TPN can cause rebound hypoglycemia.
Question 6: A patient's serum phosphorus is 1.5 mg/dL. Which condition places the patient at greatest risk for this finding?
- Malnutrition and refeeding syndrome (Correct answer)
- Chronic kidney disease
- Hypoparathyroidism
- Vitamin D toxicity
Correct answer: Malnutrition and refeeding syndrome
Hypophosphatemia is a hallmark of refeeding syndrome, where carbohydrate administration drives phosphorus into cells, depleting serum levels in malnourished patients.
Question 7: A patient's ECG shows a prolonged PR interval and widened QRS complex. Which electrolyte imbalance is most likely responsible?
- Hyperkalemia (Correct answer)
- Hyponatremia
- Hypocalcemia
- Hypomagnesemia
Correct answer: Hyperkalemia
Severe hyperkalemia progressively widens the QRS and prolongs the PR interval, which can deteriorate into ventricular fibrillation if untreated.
LPN Interpreting Lab Values and Nursing Actions 5
A patient's serum lithium level is 2.2 mEq/L.
What is the priority nursing action?