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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 helps manage mood disorders but requires careful monitoring to avoid side effects."]

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

Key facts at a glance

LOINC
9815-2
Short code
Lithium RBC-mCnc
Synonyms
Lithium RBC-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
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 helps prevent toxicity or insufficient medication levels, especially if you’re taking lithium long-term or have kidney issues that affect how it’s processed in your body.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw if instructed by your doctor. Bring a list of all medications, including supplements, to share with your provider.

What Happens During the Test?

A small needle will be inserted into your arm to draw a blood sample. You may feel a brief pinch, but it’s usually over quickly. The blood is then sent to a lab for testing.

What Are the Results Measured Against?

Results are compared to a standard range that varies by lab and individual health factors, such as kidney function. Your doctor will interpret the results in relation to your medical history and symptoms.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

High lithium levels can cause nausea, confusion, or even seizures, while low levels may mean your medication isn’t working as intended. Regular monitoring helps balance treatment to avoid these risks.

Short name

Lithium Level

Frequently asked questions

What causes lithium levels to be too high?
Overdose, dehydration, kidney problems, or taking other medications that interact with lithium can raise levels. Symptoms include vomiting, dizziness, or rapid heartbeat.
How often should I get this test?
Your doctor will determine the frequency based on your treatment plan, but it’s often checked every few months or more often if you’re experiencing symptoms or have kidney issues.
Can diet affect lithium levels?
Some foods high in sodium (like processed snacks) may influence lithium absorption, but diet changes alone won’t replace regular monitoring. Always follow your doctor’s advice.
  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