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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 dangerous buildup."]

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

Key facts at a glance

LOINC
14334-7
Short code
Lithium SerPl-sCnc
Synonyms
Lithium SerPl-sCnc
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 Matters

Lithium is prescribed to manage conditions like bipolar disorder or severe depression. Your doctor may order this test to ensure your medication is working safely and at the right dose. Too much lithium can be harmful, while too little may not control symptoms effectively.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a specific protocol. Bring your medication list to confirm if you should temporarily stop lithium or other medications.

During the Test

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to a general reference range for healthy adults, but your doctor will interpret them in the context of your symptoms, other medications, and medical history. Low levels may require a dose adjustment, while dangerously high levels need immediate medical attention.

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

How often should I get this test?
Your doctor will determine your testing schedule based on your treatment plan, but frequent checks (every 2–6 weeks) are common for stable patients to adjust doses as needed.
What causes lithium levels to change?
Several factors can affect lithium levels, including diet (salt intake), kidney function, dehydration, illness, or other medications. Stress, pregnancy, or sudden lifestyle changes may also impact results.
What symptoms might indicate a problem with my lithium levels?
Watch for signs of low levels (fatigue, weight gain, confusion) or high levels (nausea, muscle weakness, irregular heartbeat). If you experience these symptoms, contact your doctor immediately.
  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