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Lithium

Medicine levels · also printed as Lithium level, Serum lithium, Li level, Lithium (serum), Lithium carbonate level

Typical UK adult range0.4 to 1.0 mmol/L

0.4 to 1.0 mmol/L is the usual maintenance band, with some clinics aiming for 0.6 to 0.8; the treating team's target applies.

What this test measures

Lithium is a mood-stabilising medicine with a narrow band between too little and too much, so the blood level is measured regularly for as long as it is taken.

Why doctors request it

Checked every three months once stable, a week after any change, and whenever someone is unwell, dehydrated or starts a new medicine.

What commonly pushes it up

Dehydration, vomiting, diarrhoea or a hot climate
Kidney disease
Some blood pressure tablets, water tablets and anti-inflammatory painkillers as a class
A sample taken too soon after the tablet

What commonly pushes it down

Missed tablets
A high salt intake or some water tablets as a class
Pregnancy

Everyday reasons for a value outside the range

Timing is critical: the standard sample is 12 hours after the evening tablet, and an early sample reads high
Ranges differ for long-term maintenance and for acute treatment

About the sample

Blood taken 12 hours after the last evening tablet, before the morning one.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.