Lithium
Also known as: Eskalith®, Lithobid®
Use
Lithium as lithium carbonate is used as a psychoactive agent in the treatment of manic depressive disorders. Lithium therapy demands daily monitoring of serum lithium levels until the proper dose schedule is determined. Serum elimination half-life ranges from 20 to 60 hours. Insomnia in a low-range group is described. Tremor, gastrointestinal symptoms, urinary frequency, and weight gain were less frequent at lower levels.1 Intoxication never occurs suddenly. Several days to a week before full-blown symptoms develop, a patient will experience lethargy, drowsiness, tremor, muscle twitching, dysarthria, anorexia and vomiting or diarrhea. A fully developed case of intoxication shows coma to semicoma, rigidity, hyperactive reflexes and seizures at times. There is a high incidence of pulmonary complications. It is advisable to perform periodic plasma sodium determinations. Low plasma sodium levels are associated with lithium retention; high levels with lithium elimination. Varying degrees of nephrogenic diabetes insipidus have been reported to occur in 33% of lithium treated patients. Lithium significantly inhibits antidiuretic hormone induced water transport in kidney. Lithium interferes with solute and water absorption from the gastrointestinal system producing nausea, vomiting, diarrhea, and abdominal pain. These symptoms may occur at any time, at any serum level. They most commonly occur during early treatment stages and usually clear spontaneously or by adjustment of dosage. Chronic lithium administration has a goitrogenic effect on 4% of lithium treated patients, with or without hypothyroidism. In general, lithium administration results in slightly decreased serum T4 levels and transiently elevated levels of TSH in nearly 33% of these patients.
Special Instructions
Monitoring should include collection of trough serum levels just before the next dose and regular periodic plasma sodium determinations. The recommended container for specimen collection is a red-top tube or gel-barrier tube, and if a red-top tube is used, the serum should be transferred to a plastic transport tube.
Limitations
The lithium test does not diagnose any underlying conditions but is used to monitor lithium therapy in patients. Variability in lithium clearance exists among patients, and some may show no therapeutic benefit despite adequate serum concentrations if erythrocyte concentrations are low. Additionally, nephrogenic diabetes insipidus has been reported in a significant subset of lithium-treated patients, and lithium's impact on kidney function should be monitored. Lithium affects the cardiac conduction system and electrolyte balance, making regular monitoring essential.
Methodology
Other
Biomarkers
LOINC Codes
- 14334-7
- 14334-7
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube or gel-barrier tube; if a red-top tube is used, transfer separated serum to a plastic transport tube.
Collection Instructions
Collect trough level (just prior to next dose); at least 6 to 12 hours after the last dose.
Storage Instructions
Refrigerate
Causes for Rejection
Hemolysis; specimen collected in tube containing lithium heparin
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 3 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
