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Lithium concentration in serum or plasma

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

This test measures the amount of lithium, a medication, in your blood. Lithium is often prescribed to manage certain mental health conditions.

Quick summary

["Lithium helps stabilize mood and is monitored closely to ensure safe dosing."]

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

Key facts at a glance

LOINC
9358-3
Short code
Lithium Sal-mCnc
Synonyms
Lithium Sal-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 Is This Test Done?

Your healthcare provider may order this test to check if your lithium levels are within the safe range. This is especially important if you’re taking lithium to treat conditions like bipolar disorder or certain types of depression. Regular monitoring helps prevent side effects, such as toxicity, while ensuring the medication works effectively.

What to Expect During the Test

A small amount of blood is drawn from a vein in your arm. You may feel a brief pinch, but it usually doesn’t cause much discomfort. The test is quick and typically done in a lab setting. No special preparation is needed unless instructed otherwise.

Possible Causes for Testing

Tests for lithium levels may be done when you start taking lithium medication, after changes in your dose, or if you experience symptoms like nausea, vomiting, or unusual tiredness that could indicate lithium levels are too high or too low.

What the Results Mean

Results are compared to a standard range to determine if your lithium levels are appropriate. Too much lithium can cause serious health risks, while too little may mean the medication isn’t working as intended. Your provider will discuss the results with you and adjust your treatment plan if needed.

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.

◆Associated findings1

Short name

Lithium Level

Frequently asked questions

What symptoms might indicate abnormal lithium levels?
Symptoms of lithium toxicity (too much lithium) can include nausea, vomiting, confusion, muscle weakness, or irregular heartbeat. Symptoms of low lithium levels might include mood swings, anxiety, or lack of energy. Always report any unusual symptoms to your healthcare provider right away.
How often should I get this test?
Your provider will determine how often you need lithium level tests based on your treatment plan, dose, and overall health. Typically, tests may be done weekly or monthly during active treatment, then less frequently as you stabilize.
Can diet or lifestyle affect lithium levels?
Yes, certain foods, fluids, and medications can influence lithium levels. Avoiding excessive salt, staying hydrated, and following your provider’s instructions on diet and supplements can help maintain stable levels. Never change your lithium dose without consulting your healthcare provider.
  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