Current diagnostic uses of saliva

Most of the information which has been collected on salivary composition in different disease states (with the notable exception of that in digitalis intoxication) has proved of little practical diagnostic value. Diagnostic use of saliva has become more extensive in recent years, particularly in relation to estimation of systemic levels of lipid-soluble drugs and hormones. Thiocyanate levels have been used to validate self-reported frequency of tobacco-smoking, and nitrate levels have been assayed to estimate dietary nitrate intakes. The estimation of steroid hormone concentrations in saliva is now generally recognized as a means of determining systemic steroid levels which offers many advantages over estimation in serum or urine samples. Immunoassay methods now permit measurement of very small concentrations of biologically active substances in saliva.