Reliability of saliva lithium level-a prospective study.

Area of Science:

• Pharmacology
• Clinical Chemistry
• Analytical Chemistry

Background:

• Lithium therapy is crucial for managing bipolar disorder.
• Accurate monitoring of serum lithium levels is essential for therapeutic efficacy and toxicity prevention.
• Saliva offers a non-invasive alternative for drug monitoring, but its reliability for lithium needs validation.

Purpose of the Study:

• To evaluate the reliability of saliva lithium levels as an indicator of serum lithium concentration.
• To compare the predictive value of population-based and individual-based saliva/serum lithium ratios.
• To determine if saliva lithium monitoring can be a consistent alternative to serum monitoring.

Main Methods:

• Collected 140 synchronous serum and saliva samples from 28 patients on lithium therapy.
• Calculated population mean saliva/serum lithium ratio and regression line equation.
• Tested predictive values using population data and individual patient mean ratios from initial samples.

Main Results:

• The population mean saliva/serum lithium ratio was 2.68, with a regression equation Y=0.325 + 0.22X.
• Individual patient ratio prediction was more accurate than population-based prediction.
• However, no method demonstrated consistent reliability for predicting serum lithium levels from saliva.

Conclusions:

• Saliva lithium levels are not a consistently reliable indicator of serum lithium concentration.
• Current methods using saliva for lithium monitoring lack the necessary reliability for clinical use.
• Further research may be needed to refine saliva-based monitoring techniques.