Lithium blood level
Quick answer: This test measures the amount of lithium, a mood-stabilising medicine, in your blood. It is used to make sure the dose is in a safe and effective range, and when side effects or toxicity are suspected.
- SampleBlood
- TakesAbout 5 minutes
- Before the testThe sample is usually taken about 12 hours after your last dose; follow your doctor's timing and do not change your dose on your own.
- In fertility careIf you take lithium and are planning a pregnancy or are pregnant, your doctor may check levels more often, so tell them early.
How the test is done
- 1You confirm the time of your last lithium dose
- 2The sample is usually taken in the morning, about 12 hours after your evening dose
- 3Blood is drawn from a vein in your arm
- 4A plaster is applied and you take your next dose as your doctor advised
What your results can mean
Reading your report
Your doctor will compare the level with the target range for your treatment.
If the result is outside the usual range
A level above your target range can be seen with dose changes, dehydration, vomiting, kidney problems or some other medicines, and can cause side effects or toxicity. A level below range can mean the dose is not enough or doses have been missed.
Who usually has this test
People taking lithium, especially when starting, changing dose, becoming unwell or dehydrated, or starting other medicines.
Risks and aftercare
Bruising is possible, and you should seek help quickly if you notice shaking, confusion, vomiting or unsteadiness while on lithium.
Names and options
Also called: serum lithium, lithium test
Listed by the hospital as
- LITHIUM LEVEL, SERUM
Questions about this test
Why is lithium tested 12 hours after a dose?
Lithium levels rise and fall through the day after each dose. Testing about 12 hours after the last dose gives a consistent reading that doctors compare with the target range. A sample taken at a different time can be misleading.
How often are lithium levels checked?
Levels are checked often when you start lithium or change the dose, and then regularly once stable, along with kidney and thyroid tests. Your doctor will tell you how often you need it.
Can dehydration affect my lithium level?
Yes. Not drinking enough, heavy sweating, vomiting or diarrhoea can raise lithium levels. Tell your doctor if you have any of these while taking lithium.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.