The British Journal of Psychiatry 132: 152-154 (1978)
© 1978 The Royal College of Psychiatrists
Problems associated with the analysis and interpretation of saliva lithium
A Sims, AC White and K Garvey
The correlation between serum and saliva lithium levels in patients
undergoing lithium prophylaxis therapy is discussed. Although a high
correlation can be obtained, there is an unacceptably high individual
variation of paired results. Two strategies were used in an attempt to
improve the reliability of saliva as a predictor of serum levels. A
naturally occurring marker in saliva and serum was used. This showed high
correlation but still did not prevent large sporadic differences. Serially
paired results in individual patients also showed occasional excessive
variation. Although saliva lithium has been used for monitoring when serum
assessment is impracticable, it is considered that it is, as yet, an
unreliable technique.