[The value of the measurement of intra-erythrocytic lithium in the bio-clinical surveillance of lithium therapy (author's transl)].

THe correlation between red cell lithium concentration and signs of neurotoxicity have been reported in the literature by a great majority of authors. A deficiency in the lithium-sodium counter-transport mechanism may be responsible. Measurement of blood lithium levels only is not always sufficient to identify in the laboratory patients showing signs of intolerance. The three cases reported here indicate the limitations of the measurement of plasma lithium levels and the perfect correlation between neurological signs and erythrocyte levels. In vitro studies of transmembrane ion exchanges should make it possible to undertake an investigation before starting treatment in order to identify the risks of cellular toxicity.