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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, in your blood. It helps doctors monitor your dose and check for safe levels.

Quick summary

["Lithium helps manage certain mood disorders and prevents dangerous fluctuations in your medication levels."]

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

Key facts at a glance

LOINC
108824-4
Short code
Lithium Msmt SerPl
Synonyms
Lithium Msmt SerPl
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

Doctors order lithium tests to ensure your medication is working properly and to avoid side effects like toxicity. It’s often checked regularly if you’re on long-term lithium treatment for conditions like bipolar disorder or depression.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on lithium, your doctor may ask you to stop taking it for a short time before testing to get an accurate reading.

What the Results Mean

Results are compared to a general reference range, but exact values can vary by lab. Too little lithium may mean your medication isn’t working, while too much can be harmful. Your doctor will discuss your specific results with you.

Common Causes of Abnormal Results

Low lithium levels might occur if your body excretes it too quickly or if you’re not taking enough. High levels can result from overuse, dehydration, or certain kidney problems. Other factors, like diet or stress, may also affect results.

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.

Clinical Significance

Short name

Lithium Level

Frequently asked questions

How often do I need this test?
Your doctor will determine how often you need lithium tests based on your treatment plan, how long you’ve been on the medication, and your overall health. Typically, it’s checked every few weeks to months during active treatment.
What if my test results are out of range?
If your results are too high, your doctor may adjust your dose or suggest lifestyle changes (like reducing salt intake) to help your body process lithium better. If too low, they might increase your medication. Always follow their guidance.
Can I eat or drink before the test?
You can eat and drink normally before the test, but avoid foods high in salt (like processed snacks) for 24 hours before, as salt can affect lithium levels.
  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