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Lithium Concentration in Serum/Plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of lithium, a medication used to treat certain mental health conditions, in your blood.

Quick summary

["Lithium levels help doctors monitor your treatment and prevent potential side effects."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
3723-4
Short code
Lithium Trough SerPl-mCnc
Synonyms
Lithium Trough SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.6
Ref high
1.2
Critical range
— – 1.6 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you’re taking lithium medication to manage conditions like bipolar disorder or severe depression. Regular monitoring helps ensure your dose is safe and effective.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from a vein in your arm. The process is quick and typically painless.

What the Results Mean

Results help your doctor check if your lithium levels are within the target range for your condition. Too little or too much can affect your health differently.

Common Causes of Abnormal Results

High lithium levels may occur if you’re taking too much lithium or have kidney problems. Low levels could happen if your body is excreting it too quickly or if you’re not taking enough.

Reference range

Therapeutic: 0.6-1.2 mmol/LN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Lithium levels are critical because they can cause serious side effects if not properly managed. Too much lithium can damage organs, while too little may not control symptoms effectively. Regular monitoring is essential for safety and treatment success.

Short name

Lithium Level

Frequently asked questions

Why do doctors check lithium levels frequently during treatment?
Doctors check lithium levels frequently to balance your medication dose and prevent side effects like nausea, tremors, or kidney issues. It also helps ensure your mental health symptoms improve without harming your body.
What happens if my lithium level is too high?
If your lithium level is too high, your doctor may adjust your dose, monitor you closely, or recommend fluids to help flush it out. Severe cases may require emergency treatment.
Can diet or other medications affect lithium levels?
Yes, foods high in sodium, certain diuretics, or other medications (like NSAIDs) can change lithium levels. Always tell your doctor about all medications and foods you’re taking.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy