# The nurse is reviewing baseline laboratory monitoring for a client newly prescribed long-term lithium therapy. Which set of tests is most important before and during therapy?

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> language: en  
> subject: Medical Emergencies  
> category: PA

## Question

The nurse is reviewing baseline laboratory monitoring for a client newly prescribed long-term lithium therapy. Which set of tests is most important before and during therapy?

## Option

1. Only liver enzymes because lithium is primarily metabolized by the liver.
2. Creatinine/BUN, electrolytes, TSH, pregnancy status when applicable, and serum lithium levels. **✔ Correct answer**
3. Peak lithium levels 30 minutes after each dose and daily platelet counts.
4. Weekly troponin and BNP because lithium commonly causes myocardial infarction.

**Correct answer: 2**

## Explanation

Lithium is not hepatically metabolized; it is primarily renally cleared and can affect thyroid function. Baseline and ongoing monitoring should include renal function, electrolytes/sodium, thyroid function, pregnancy status when relevant, and scheduled serum lithium levels.

## In-depth explanation

Clinical Practice Guide Before chronic lithium: check kidney function, sodium/electrolytes, thyroid status, pregnancy status when relevant, and establish a monitoring plan for 12-hour trough levels.

## Clinical scenario

Scenario New long-term lithium prescription; baseline safety labs needed.

## Key concepts

- **Renal function** — Reduced GFR decreases lithium clearance and raises toxicity risk; monitor creatinine/BUN and hydration status.
- **Thyroid function** — Lithium can cause hypothyroidism and goiter; monitor TSH and symptoms such as fatigue, weight gain, and cold intolerance.
- **Pregnancy screening** — Lithium carries fetal risk, especially first trimester cardiac malformations; discuss risks and alternatives.

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