After taking lithium drug for one month, a patient checked their serum lithium level and found it to be 1.0 mEq/L. The nurse checked the report and noted it in the nurse's record. What is the correct interpretation of the report?

Appeared in: DSSSB 6 September 2024

Explanation

The patient's serum lithium level of 1.0 mEq/L falls within the standard therapeutic maintenance range.
The accepted therapeutic range for maintenance lithium therapy is typically 0.6 to 1.2 mEq/L.
A level of 1.0 mEq/L indicates that the current dosage is effective for managing the patient's condition without being toxic.
This level is ideal for long-term prophylaxis of bipolar disorder.

Why Other Options Were Wrong

Option B: A level of 1.0 mEq/L is not considered toxic. Lithium toxicity generally begins to manifest at levels greater than 1.5 mEq/L.
Option C: A level of 1.0 mEq/L is well above the subtherapeutic threshold. Levels below 0.6 mEq/L are considered subtherapeutic.
Option D: A level of 1.0 mEq/L is not above the therapeutic range, as the upper limit for maintenance is 1.2 mEq/L.

Related Visual

Clinical Relevance

Nursing practice connection: Safe nursing care depends on performing Interpretation of serum lithium levels in the correct sequence, documenting the action clearly, and monitoring for the expected response.
Lithium has a very narrow therapeutic index, making regular blood level monitoring a critical patient safety measure to prevent life-threatening toxicity.
Nurses play a key role in educating patients about the importance of consistent fluid and sodium intake, as imbalances can drastically alter lithium levels.
What if? If the patient's level was 1.6 mEq/L and they reported fine hand tremors, ataxia, and diarrhea, the nurse's priority action would be to withhold the next dose of lithium and immediately notify the prescribing physician, as these are clear signs of toxicity.

How to Approach the Question

First, identify the core of the question, which is to interpret a specific lab value for a specific drug.
The key information is the drug (lithium) and the lab result (1.0 mEq/L).
Recall the standard therapeutic range for lithium. For maintenance, this is typically 0.6-1.2 mEq/L.
Compare the patient's value (1.0 mEq/L) to this known range.
Evaluate each option: 1.0 is within the 0.6-1.2 range, not below, not above, and not toxic.
Select the option that accurately describes the relationship between the patient's value and the standard range.

Concept Tested & Keywords

Concept Tested: Interpretation of serum lithium levels
Stem keywords: lithium, serum lithium level, 1.0 mEq/L
Lead-in keywords: correct interpretation
Clinical cues: Patient taking lithium for one month
Clinical cues: Serum level is 1.0 mEq/L

Question ID

QZlOlMxkAkOH904CaF2onO

Reference Book

E6 Robert Boland, Marcia L. Verduin - Kaplan and Sadock's Comprehensive Text of Psychiatry-Wolters Kluwer Health (2024) (pp 1-16525 of 16525) pp. 3494-3496, 10750-10752

E6 Kaplan Sadock's Synopsis of Psychiatry-2022 (pp 1-3768 of 3768) p. 2065-2067

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