The lithium ions concentration in human serum and saliva was determined using dry-slide technology Vitros 250 Analyser (Ortho Clinical Diagnostic) and atomic absorption spectrometry Perkin Elmer 403 (AAS). We analyzed lithium ions in 100 serum and saliva specimens of patients after oral administration of lithium carbonate (3 x 300 mg) Jadran, Galen Laboratory Rijeka. Saliva and blood were taken 2 and 12 hours after the last dose. At the same time lithium ions at samples of blood and saliva were determined with both methods which showed high level of correlation. The mean difference of lithium ions between saliva and serum was statistically significant for p<0.05 using t student test. At saliva we got constant of elimination Kel = 0.02(-1)h and elimination half life (t(1/2)) was t(1/2)=34.6 h. For serum was t(1/2)= 24 h what means that lithium ions elimination is slower from saliva then from serum. That is the reason why probably concentration at saliva is higher then at serum. Lithium elimination is two compartment pharmacokinetic model where important part of compartment are saliva and salivary glands. At a certain point in medical treatment it could be expected to use controlled determination of lithium ions in saliva with serum as control.

The lithium ions concentration in human serum was determined using Dry-slide technology Vitros 250 Analyser (Ortho Clinical Diagnostic), atomic absorption spectrometry (AAS) method Perkin Elmer 403 and ion-selective electrode (ISE) potentiometry AVL 9181. We compared lithium ions results in sample sera between these methods. Our reference method was AAS. We analyzed lithium ions concentration in 23 sera samples of patients after oral administration of lithium carbonate (3x 300mg) Jadran, Galen Laboratory Rijeka, by dry-slide technology, AAS and ISE methods. The quality control, precision, reproducibility and accuracy for Vitros dry slide technology were assessed. We established that the main difference between AAS method and dry slide technology was not statistically significant at p< 0.05 according to Student t-test. Therefore, the dry slide technology may be a useful alternative or it may even replace other methods, such as AAS. The main difference between dry slide technology and ISE methods was statistically significant at p<0.05 using Student t-test. By ISE method, we obtained considerably higher results, which may be explained by the presence of electrolytes or medicaments interfering with lithium ions.