The ability to monitor the health and disease status of the patient through saliva is a highly desirable goal for the health professionals. Considering the microconcentration of salivary constituents, saliva is explored to be diagnostic tool as it also meets the demands for an inexpensive, noninvasive and easy to use screening method. The incorporation of salivary diagnostics into clinical practice is gaining reality and will be of diagnostic value in the prospective future. The investigative use of saliva is not being applied only in dental health but also in various other systemic disorders. The advent of molecular techniques is gaining attention and this has triggered its application as a specific and sensitive biomarker in proteomics, genomics, and transcriptomics. This review discusses the basics of salivary diagnostics, expectoration techniques, and its application in various local and systemic disorders. 1. Introduction Saliva is a unique biologic dynamic fluid that has varying spectrum of proteins, polypeptides, nucleic acids, electrolytes, and hormones. It is an exocrine secretion of the salivary glands which is hypotonic in nature with a pH of 7.2–7.4 [1]. The diagnostic potential of saliva is reflected by the presence of multiple biomarkers which appears at a concentration much lesser than blood and still serves as a mirror reflecting the body’s health and wellbeing [2]. Saliva is a product of three major salivary glands: parotid, submandibular, and sublingual with added secretions from minor salivary gland [3]. The variety of enzymes, hormones, antibodies, antimicrobial constituents, and growth factors are incorporated into the saliva from the blood through the transcellular and paracellular routes [4]. Hence saliva bears a functional equivality with the serum and reflects the physiological state of the body, including nutritional, emotional, hormonal, and metabolic variations [5]. 2. Salivary Diagnostics The field of salivary diagnostics came into existence in the 1960s when salivary calcium levels were found to be raised in cystic fibrosis patients. In the recent years, the field broadened in various horizons, including detection of cancers, heart disease, and infectious diseases. It is also used to diagnose the HIV infections and in detection of the levels of drug, hormone, and alcohol. The improved efficiency and accuracy of genomic and proteomic biomarkers are turning salivary diagnostics into a clinical and commercial reality [6]. 3. Leverage of Saliva over Serum Saliva is gaining importance in recent years and is considered a
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