Overview
Lithium concentration guides mood-stabilizer dosing and toxicity assessment.
Clinical Importance
Lithium TDM and suspected toxicity
Specimen Requirements
- Specimen: serum preferred (SST/red-top); some methods accept sodium heparin plasma; follow the performing laboratory
- Do not use lithium heparin tubes; the additive contaminates the lithium assay and falsely elevates results
- Handling: allow SST to clot fully; centrifuge and separate promptly
- Draw 12-hour post-dose trough at steady state unless otherwise directed
Analytical Method
ISE, colorimetric, or atomic absorption/flame methods.
Instruments Used
Automated analyzers
- Roche Cobas chemistry and immunoassay systems
- Abbott Alinity / Architect chemistry and immunoassay systems
- Siemens Healthineers Atellica / ADVIA chemistry and immunoassay systems
- Beckman Coulter AU / DxC chemistry systems
- Beckman Coulter Access / DxI immunoassay systems
- Mindray BS-series chemistry analyzers
- Ortho Clinical Diagnostics Vitros systems
- Thermo Fisher / Indiko and related chemistry platforms
- Randox clinical chemistry systems
Manual methods
- Manual spectrophotometric/immunoassay methods in selected reference or backup settings
Reference Values
Typical adult SI examples below follow widely published international clinical chemistry practice (e.g., Tietz; Henry's). Always interpret against the method- and demographics-specific interval printed on the patient report (CLSI EP28-A3c). Neonatal, pediatric, pregnancy, and assay-generation intervals differ.
Typical maintenance trough targets often about 0.6–1.2 mmol/L depending on indication; toxicity risk rises as levels approach/exceed ~1.5 mmol/L. Verify local targets.
Interpretation
Critical and significant-risk limits are institution-defined (CLSI GP47). Confirm the local call list. Textbook examples are not universal thresholds.
Critical values
- Toxic lithium levels are commonly critical; verify locally
Common Causes of Increased Results
- Supratherapeutic/toxic lithium
Common Causes of Decreased Results
- Subtherapeutic
Clinical Significance
- Psychiatry TDM
Factors Affecting Results
Pre-analytical
- Wrong timing; dehydration raising levels
- Lithium heparin tube contamination (false high)
Analytical
- Calibration/QC failure; reagent lot shifts
- Carryover or substrate depletion on high-throughput analyzers
- Assay-specific interference (heterophile antibodies for immunoassays)
Post-analytical
- Wrong reference interval or unit applied
- Failure to review delta checks / critical values before release
Advantages and Limitations
Advantages
- Essential for safe lithium use
Limitations
- Kidney function and sodium balance alter levels
Clinical Pearls
Lithium without a 12-hour trough time is guessing; and a lithium-heparin tube invents toxicity.
References
Authoritative textbooks, guidelines, and reviews supporting this laboratory test reference. Verify reference intervals, critical limits, and method details against institutional protocols and current guideline editions.
Textbooks
- Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 8th ed. Elsevier; 2022.
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2021.
- Bishop ML, Fody EP, Schoeff LE. Clinical Chemistry: Principles, Techniques, and Correlations. 9th ed. Jones & Bartlett; 2022.
CLSI and Professional Guidelines
- International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Recommendations and reference measurement systems for clinical chemistry measurands (verify current IFCC documents for the analyte).
- Clinical and Laboratory Standards Institute. Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Standard. CLSI document EP28-A3c. CLSI; 2010.
- Clinical and Laboratory Standards Institute. Collection of Diagnostic Venous Blood Specimens. CLSI standard GP41. CLSI.
- American Diabetes Association. Standards of Care in Diabetes. Diabetes Care (annual update).
- Kidney Disease: Improving Global Outcomes (KDIGO). Clinical Practice Guideline for Evaluation and Management of Chronic Kidney Disease.
- American Association for the Study of Liver Diseases (AASLD). Practice guidance related to evaluation of abnormal liver chemistries / liver disease laboratory evaluation (verify current AASLD publication and institutional adoption).
Frequently Asked Questions
Common questions about using this Lithium laboratory test Medical Laboratory Library reference in Medical Laboratory Science education.
What is the Lithium laboratory test reference used for?
This Medical Laboratory Library page summarizes the clinical importance of Lithium. Review the Clinical Importance section for why the test is ordered in laboratory medicine practice.
Where can I find Lithium specimen requirements?
See the Specimen Requirements section on this page for specimen information related to Lithium. Confirm collection details against your laboratory protocol.
Where are Lithium reference values listed?
See the Reference Values section on this Laboratory Library page. Reference ranges can vary by method and population, so verify intervals with your laboratory.
How do I interpret Lithium results?
Use the Interpretation section for laboratory interpretation framing, including increased and decreased result patterns when provided. Do not treat educational text as a patient-specific diagnosis.
What analytical method is used for Lithium?
See the Analytical Method section for principle and method notes. Method details may differ by instrument and institutional SOP.
Are related laboratory tests linked from Lithium?
Yes. The Related Laboratory Tests section lists connected references for continued lookup in the Medical Laboratory Library.
How can I continue learning after reading Lithium?
Use Continue learning links on this page for related Academy lessons, medical laboratory quizzes, or laboratory case studies when available for this Clinical Chemistry topic.
What are the clinical pearls for Lithium?
See the Clinical Pearls section for concise laboratory practice notes associated with Lithium. Apply pearls alongside institutional protocols.
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