Salivary Diagnostics: Are We There Yet?

Charles F. Streckfus, DDS, MA


November 13, 2012

In This Article
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Saliva: Mirror of the Human Body

Saliva is an exocrine secretion produced by 3 pairs of major glands and numerous minor glands located throughout the oral mucosa. In humans, saliva is the first step in digesting food. It maintains the mineralization of the teeth, moisturizes and protects the oral mucosa, and is necessary for speech and swallowing food. It is also essential for the inhibition of serious systemic pathogens. A little known fact about saliva, however, is that this unique medium can be used as a diagnostic fluid.

Saliva as a diagnostic fluid is the "holy grail" for scientists and clinical researchers involved in the development of an analytic instrument. It is easy to collect and noninvasive, can be collected repeatedly without discomfort to the patient, and can be obtained in a variety of settings ranging from health fairs to roadside law enforcement procedures. The applications are limitless.

The late Dr. Irwin Mandel[1,2,3] explained that salivary diagnostics have origins in ancient China through use of the "rice test." A person accused of a crime was given a mouthful of dry rice. If guilty, anxiety inhibited salivation so that the defendant could not form an adequate bolus for chewing and swallowing.[2]

From these humble beginnings, saliva has been considered to be a "mirror of the human body," able to reflect an individual's emotional, hormonal, immunologic, and neurologic status.[2] Saliva is also an indicator of nutritional and metabolic influences and tissue fluid levels of natural substances, as well as molecules introduced for therapeutic or recreational purposes.[2] However, the real advantage of saliva is that it is not, biochemically speaking, as complex as blood.