Lithium: What Your Result Means

What is Lithium?

Lithium is one of the most effective mood stabilizers for bipolar disorder, but it has a narrow therapeutic window — the difference between an effective level and a toxic one is small. Regular blood monitoring is essential, especially after dose changes, during illness, or when other medications change. Levels are also affected by dehydration, kidney function, and sodium balance.

Typical reference interval: Therapeutic lithium levels are typically kept in a defined range (commonly around 0.6-1.2 mmol/L, depending on the indication) measured about 12 hours after the last dose. Levels above the therapeutic range raise toxicity risk; levels below may not be effective. Your prescriber sets your target.. Laboratories differ — the interval printed on YOUR report always governs.

If your Lithium is high

Common reasons Lithium runs above the reference interval:

• Too high a dose — the most common cause of elevated lithium — a reason doses are adjusted slowly
• Dehydration or low sodium — the body retains lithium when sodium is low, raising blood levels
• Kidney function changes — lithium is cleared by the kidneys, so kidney impairment raises levels
• Drug interactions — some blood-pressure, pain, and other medications raise lithium levels
• Illness with fever or vomiting — these states can shift lithium levels quickly

If your Lithium is low

Common reasons Lithium runs below the reference interval:

• Dose too low or missed doses — a level below the therapeutic range may not control mood symptoms
• Increased clearance — some states increase lithium removal, lowering levels
• Timing of the blood draw — testing too soon after a dose can read falsely high or low depending on timing — consistent timing matters

Symptoms worth knowing

Lithium toxicity causes nausea, tremor, confusion, unsteadiness, and in severe cases seizures — symptoms that require urgent medical attention. Low levels do not cause symptoms but may leave mood symptoms undertreated. The number is monitored to keep you in the safe, effective zone.

What usually happens next

1. Lithium levels are interpreted by your prescriber — never adjust your dose on your own
2. Keep blood draws at the same time relative to your last dose, usually about 12 hours after, for consistent results
3. Report vomiting, diarrhea, fever, or new medications promptly, since these can raise lithium to dangerous levels

Frequently asked questions about Lithium results