The origins of salivary diagnostics go back some 60 years when it was found that people suffering from cystic fibrosis had above-normal levels of calcium in saliva. However, despite of carrying a number of biomarkers for systemic and local conditions, the field of salivary diagnostics had languished until a few years back.
One of the main reasons for the preference of blood and urine testing as modalities for diagnosis and prognosis was that enzymes, proteins and antibodies were always easier to isolate with these fluids. But things have changed over the past decade. The unraveling of the human salivary proteome, and advances in nanotechnology and microbiology have led to a renewed interest in salivary diagnostics.
Human saliva can now be used to detect autoimmune conditions such as multiple sclerosis, Sjogren's syndrome, sarcoidosis, metabolic bone disorders, cardiovascular conditions, periodontal conditions, genetic diseases, genetic disorders, and fungal, bacterial and viral infections.
The use of saliva for diagnosis offers some clear advantages over blood. Sample collection is noninvasive, which makes saliva an ideal choice for patients with sunken veins, obese individuals and hemophiliacs. Saliva does not clot and therefore is easier to store and transport. With easy-to-use kits, saliva tests can also be self-administered.
Saliva, as a monitoring agent, can be used for monitoring drug levels. It holds special significance for the testing of illegal drugs and can be used to control drug trafficking, solve criminal cases and administer medical aid quickly. The amount of drugs such as methamphetamine and cocaine in saliva has a direct correlation to the amount in the blood.
Salivary diagnostics plays an important role in the field of forensics. Saliva can be obtained from objects such as cigarettes and glasses found at a crime scene. It can be used to determine the presence of foreign DNA.
Quick results promised by salivary diagnostics are a major attraction for dental practitioners. In a recent poll, 83.4 percent of dentists expressed interest in salivary diagnostics as a painless chair-side option if results were generated quickly. Nearly 46 percent indicated a willingness to conduct screenings in the office and send samples out for analysis.
Support for salivary diagnostics in the medical community can be assessed from a paper presented in 2010. The paper states that physicians are ready to welcome results from salivary diagnostics conducted in dental clinics for hypertension, diabetes mellitus, HIV infection and cardiovascular disease. And they would be open to patient referrals from dentists.
The use of saliva for diagnosis is preferable for infants, children, geriatrics and for remotely located populations. Also, the use of saliva for children will yield data that can be used for creating accurate medicine dosages for them. At present, it is common practice to use data from adults and then use the results to come up with a protocol for children.
Successful identification of biomarkers linked to diseases and conditions, and the development of new technology to measure these biomarkers in saliva will determine the future growth of salivary diagnostics.
