From the Guidelines
Lithium screening labs should include complete blood cell counts, thyroid function tests, urinalysis, blood urea nitrogen, creatinine, and serum calcium levels before initiation of therapy, as well as regular monitoring of lithium levels, renal and thyroid function, and urinalyses every 3-6 months. When considering lithium therapy, it is crucial to assess baseline laboratory values to ensure safe and effective treatment 1. The initial laboratory assessment should include:
- Complete blood cell counts
- Thyroid function tests
- Urinalysis
- Blood urea nitrogen
- Creatinine
- Serum calcium levels
- Pregnancy test in female adolescents Regular monitoring is also essential to prevent potential adverse effects, such as renal or thyroid dysfunction 1. Ongoing monitoring should include:
- Lithium levels
- Renal function tests (every 3-6 months)
- Thyroid function tests (every 3-6 months)
- Urinalyses (every 3-6 months) By following this comprehensive screening approach, clinicians can minimize the risk of lithium toxicity while maximizing its therapeutic benefits 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION ... Regular monitoring of the patient’s clinical state and of serum lithium levels is necessary. Serum levels should be determined twice per week during the acute phase, and until the serum level and clinical condition of the patient have been stabilized. ... Serum lithium levels in uncomplicated cases receiving maintenance therapy during remission should be monitored at least every two months. ... Blood samples for serum lithium determination should be drawn immediately prior to the next dose when lithium concentrations are relatively stable (i.e., 8-12 hours after the previous dose).
- Lithium screening labs should include serum lithium levels.
- These levels should be:
- Checked twice per week during the acute phase.
- Monitored at least every two months during maintenance therapy.
- Blood samples should be drawn 8-12 hours after the previous dose, immediately prior to the next dose, when lithium concentrations are relatively stable 2.
From the Research
Lithium Screening Labs
Lithium therapy requires regular monitoring of various laboratory tests to minimize the risk of side effects and ensure effective treatment. The following are some key laboratory tests that are recommended for patients receiving lithium therapy:
- Serum lithium levels: to ensure that the levels are within the therapeutic range (0.4 to 1.2 mmol/L) 3
- Serum calcium and parathyroid hormone (PTH) levels: to monitor for hypercalcemia and primary hyperparathyroidism 4
- Thyroid function tests (TSH, free T4, and free T3): to monitor for thyroid disorders, such as hypothyroidism and hyperthyroidism 4
- Renal function tests (serum creatinine, blood urea nitrogen, and estimated glomerular filtration rate (eGFR)): to monitor for renal insufficiency and nephrogenic diabetes insipidus 4, 5, 6
- Urinalysis: to monitor for proteinuria and hematuria 6
- Spot urine protein/creatinine ratio: to detect lithium-induced nephropathy 6
Frequency of Laboratory Tests
The frequency of laboratory tests may vary depending on the individual patient's needs and the duration of lithium therapy. However, the following are some general guidelines:
- Serum lithium levels: every 3-6 months 3
- Serum calcium and PTH levels: every 6-12 months 4
- Thyroid function tests: every 6-12 months 4
- Renal function tests: every 6-12 months 4, 5, 6
- Urinalysis: every 6-12 months 6
- Spot urine protein/creatinine ratio: every 6-12 months 6
Special Considerations
Patients with pre-existing renal or thyroid disease may require more frequent laboratory tests and closer monitoring of their lithium levels 4, 5, 6. Additionally, patients who develop side effects or have changes in their medical condition may require more frequent laboratory tests and adjustments to their lithium therapy 4, 5, 7, 6.