Saliva testing

Saliva nitric test strip (Berkeley Test) showing colored scale of nitric oxide status – See article and jump to Cardiovascular Disease, Nitric Oxide: a salivary biomarker for cardio-protection

Saliva testing or Salivaomics is a diagnostic technique that involves laboratory analysis of saliva to identify markers of endocrine, immunologic, inflammatory, infectious, and other types of conditions. Saliva is a useful biological fluid for assaying steroid hormones such as cortisol, genetic material like RNA, proteins such as enzymes and antibodies, and a variety of other substances, including natural metabolites, including saliva nitrite, a biomarker for nitric oxide status (see below for Cardiovascular Disease, Nitric Oxide: a salivary biomarker for cardio-protection). Saliva testing is used to screen for or diagnose numerous conditions and disease states,[1] including Cushing's disease, anovulation, HIV, cancer, parasites, hypogonadism, and allergies. Salivary testing has even been used by the U.S. government to assess circadian rhythm shifts in astronauts before flight and to evaluate hormonal profiles of soldiers undergoing military survival training.[2][3]

Proponents of saliva testing cite its ease of collection, safety, non-invasiveness, affordability, accuracy, and capacity to circumvent venipuncture as the primary advantages when compared to blood testing and other types of diagnostic testing. Additionally, since multiple samples can be readily obtained, saliva testing is particularly useful for performing chronobiological assessments that span hours, days, or weeks. Collecting whole saliva by passive drool has a myriad of advantages. Passive drool collection facilitates large sample size collection. Consequently, this allows the sample to be tested for more than one biomarker. It also gives the researcher the ability to freeze the left over specimen to be used at a later time. Additionally, it lessens the possibility of contamination by eliminating extra collection devices and the need to induce saliva flow.[4]

The testing of salivation by the use of mercury was performed at least as early as 1685.[5] Testing the acidity of saliva occurred at least as early as 1808.[6] The clinical use of saliva testing occurred at least as early as 1836 in patients with bronchitis.[7] In 1959, scientists in the journal Cancer raised the possibility of using biochemical changes in acid phosphatases in saliva as an indicator of the presence of prostate cancer.[8]

More recent studies have focused on detection of steroid hormones and antibodies in the saliva. Recent applications emphasize the development of increasingly sophisticated techniques to detect additional proteins, genetic material, and markers of nutritional status. According to Wong, scientists are now viewing saliva as "a valuable biofluid…with the potential to extract more data than is possible currently with other diagnostic methods."[9]

  1. ^ Nonaka T, Wong DT (13 June 2022). "Saliva Diagnostics". Annual Review of Analytical Chemistry. 15 (1): 107–121. Bibcode:2022ARAC...15..107N. doi:10.1146/annurev-anchem-061020-123959. ISSN 1936-1327. PMC 9348814. PMID 35696523. S2CID 249644061.
  2. ^ Morgan CA, Wang S, Mason J, et al. (May 2000). "Hormone profiles in humans experiencing military survival training". Biol. Psychiatry. 47 (10): 891–901. doi:10.1016/s0006-3223(99)00307-8. PMID 10807962. S2CID 36241351.
  3. ^ Whitson PA, Putcha L, Chen YM, Baker E (April 1995). "Melatonin and cortisol assessment of circadian shifts in astronauts before flight". J. Pineal Res. 18 (3): 141–7. doi:10.1111/j.1600-079x.1995.tb00152.x. PMID 7562371. S2CID 37522924. Archived from the original on 2021-11-23. Retrieved 2019-11-30.
  4. ^ Granger Douglas A., Kivlighan Katie T., Fortunato Christine, Harmon Amanda G., Hibel Leah C., Schwartz Eve B., Whembolua Guy-Lucien (2007). "Integration of Salivary Biomarkers into Developmental and Behaviorally-oriented Research: Problems and Solutions for Collecting Specimens". Physiology & Behavior. 92 (4): 583–90. doi:10.1016/j.physbeh.2007.05.004. PMID 17572453. S2CID 22420479.
  5. ^ Nicolas de Blégny (1685). Zodiacus Medico-Gallicus, sive miscellaneorum curiosorum, medico-physicorum sylloge. Vol. 5. Chouët. p. 149.
  6. ^ Nicholson, William (1808). A Dictionary of Practical and Theoretical Chemistry: With Its Application to the Arts and Manufactures, and to the Explanation of the Phaenomena of Nature...: with Plates and Tables. Richard Phillips. p. 2 R 2.
  7. ^ Johnson J, Johnson HJ, eds. (1836). "On the Chemical Condition of the Saliva, as an Indication of the difference Morbid Affections of the Stomach". The Medico-chirurgical Review and Journal of Practical Medicine. 24. Richard & George S. Wood: 231, 233.
  8. ^ Loewy MA (14 March 2023). "Saliva: The next frontier in cancer detection". Knowable Magazine. doi:10.1146/knowable-031323-1. Archived from the original on 24 March 2023. Retrieved 20 March 2023.
  9. ^ Wong DT (March 2006). "Salivary diagnostics powered by nanotechnologies, proteomics and genomics". J Am Dent Assoc. 137 (3): 313–21. doi:10.14219/jada.archive.2006.0180. PMID 16570464. S2CID 4828883.