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Also known as: [Often referred to by brand name (see MedlinePlus Drug Information)]
Formal name: Lithium

At a Glance

Why Get Tested?

To determine lithium levels in the blood in order to maintain a therapeutic level or to detect lithium toxicity

When to Get Tested?

When beginning treatment with lithium as the dose is adjusted to achieve therapeutic blood levels; at regular intervals to monitor lithium levels; as needed to detect low or toxic concentrations

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?


The Test Sample

What is being tested?

Lithium is one of the most well-established and widely-used drugs prescribed in the treatment of bipolar disorder. This test measures the amount of lithium in the blood.

Bipolar disorder is a mental condition characterized by alternating periods of depression and mania. These periods may be as short as a few days or weeks or as long as months or years. During a depressive episode, those affected may feel sad, hopeless, worthless, and lose interest in daily activities. They may be fatigued but have trouble sleeping, experience weight loss or gain, have difficulty concentrating, and have thoughts of suicide. During a manic episode, those affected may be euphoric, irritable, have high energy and grandiose ideas, use poor judgment, and participate in risky behaviors. Sometimes affected people will have mixed episodes with aspects of both mania and depression. Bipolar disorder can affect both adults and children.

Lithium is prescribed to even out the moods of a person with bipolar disorder. It is often called a "mood stabilizer" and is sometimes prescribed for people with depression who are not responding well to other medications. Less commonly, lithium may be prescribed to prevent schizoaffective disorder and cluster headaches.

Because lithium is a relatively slow-acting drug, its effect on mood may take several weeks. Dosages of the drug are adjusted until blood concentrations are within a therapeutic range. The actual amount of drug that it will take to reach this steady state will vary from person to person and may be affected by a person's age, general state of health, and other medications that they are taking.

Lithium levels are monitored on a regular basis because blood levels must be maintained within a narrow therapeutic range. Too little and the medication will not be effective; too much and symptoms associated with lithium toxicity may develop.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed. However, timing of the sample collection may affect results. Generally, lithium blood levels are performed 12 hours after the last dose (also known as a "trough" level). Tell the person who draws your blood when you took your last dose so that the results can be interpreted correctly.

The Test

Common Questions

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

C. Wijeratne and B. Draper. Reformulation of current recommendations for target serum lithium concentration according to clinical indication, age and physical comorbidity. Aust N Z J Psychiatry. 2011 Dec; 45(12):1026-32. Available online at through Accessed July 17, 2013.

Serum lithium measurement. MUSC Health: Medical University of South Carolina. Available online at through Accessed July 17, 2013.

Lithium. Egton Medical Information Systems Limited. Available online at through Last reviewed 02/05/2013. Accessed July 17, 2013.

Label and Approval History. Food and Drug Administration. PDF available for download at,18152slr020_eskalith_lbl.pdf through Issued 2004. Accessed July 17, 2013.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006 Pp 608-609.

Sources Used in Previous Reviews

Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp 1121.

Spearing, M. Updated (2006 February 17,Updated). Bipolar Disorder. NIMH [On-line information]. Available online at through

Goldberg, J. and Citrome, L. (2005 February). Latest therapies for bipolar disorder, Looking beyond lithium. Postgraduate Medicine online v 117 (2) [On-line journal]. Available online at through

Geddes, J. et. al. (2004 February). Long-Term Lithium Therapy for Bipolar Disorder: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Psychiatry 161:217-222 [On-line journal]. Available online at through

Newport, D. J. et. al. (2005 November). Lithium Placental Passage and Obstetrical Outcome: Implications for Clinical Management During Late Pregnancy. American Journal of Psychiatry 162:2162-2170 [on-line abstract]. Available online at through

Schapiro, N. (2005). Bipolar Disorders in Children and Adolescents. Medscape from J Pediatr Health Care. 2005; 19 (3): 131-141 [On-line information]. Available online at through

Menon, L. (2005 August, Updated). Lithium. National Alliance for the Mentally Ill [On-line information]. Available online through

Walling, A. (2005 January 1). Evidence-Based Guidelines for Bipolar Disorder Therapy. American Family Physician [On-line journal]. Available online at through

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER and Bruns DE, eds. 4th ed. St. Louis, Missouri: Elsevier Saunders; 2006, Pp 1271-1272.

Harrison's Principles of Internal Medicine. 16th ed. Kasper D, Braunwald E, Fauci A, Hauser S, Longo D, Jameson JL, eds. McGraw-Hill, 2005 Pg 2557.

(Updated March 24, 2009) Lee D, Gupta M. Toxicity, Lithium from Medscape. Available online at through Accessed September 2009.

(January 15, 2009) MedlinePlus Medical Encyclopedia. Bipolar Disorder. Available online at Accessed September 2009.

(January 4, 2009) Mayo Clinic. Bipolar Disorder. Available online at through Accessed September 2009.

National Alliance on Mental Illness. Medications, Lithium. Available online through Accessed September 2009.

(Jan 14, 2009) Lloyd A. Netdoctor: Lithium. Available online at through Accessed September 2009.