Human saliva is 99% water. However, saliva testing provides vital insights into your patients’ health and wellness. The remaining 1% is made up of salivary proteins, gingival crevicular fluid, bacterial compounds, enzymes, and foundational health biomarkers. These salivary biomarkers may highlight health concerns, aid in prevention, and inform diagnosis. Recent evidence validates saliva as a mediator of the physiological condition. Saliva expresses markers related to hormonal, organ, overall health, and the risk of certain diseases.
The combined secretions from all salivary glands (i.e., whole saliva) is easily collected and highly informative. As a noninvasive alternative, saliva panels are nevertheless accurate. Salivary testing is even ideal for documentation such as point-of-care testing. Altogether, these qualities show saliva is a biofluid with immense translational, functional, and clinical potential.
The use of saliva as a diagnostic tool is decades old. Saliva has long been used to measure hormone levels, isolate viral antibodies, analyze immune health, and more. Many of the foundational health markers in saliva are connected to the salivary proteome and microbiome.
For the healthy individual, salivary flow directly relates to oral cavity health. Saliva’s antimicrobial effects inhibit damaging pathogens, neutralize acid production, and repair mouth tissue. By fighting against oral diseases such as gingivitis, dental caries, and periodontal disease, saliva plays an integral role in oral health. Saliva also lubricates mouth tissue, aids mastication, and promotes metabolism. This role of saliva in oral health and dentistry is connected to its greater function in whole-body health.
One significant connection between salivary composition and health markers is periodontal disease. Evidence from a cross-sectional study shows that the levels of matrix metalloproteinase-8 (MMP-8) and the cytokine interleukin-1 beta (IL-1β) found in the saliva are instrumental to diagnosing periodontal disease. These markers are also related to conditions of chronic inflammation and heart disease. The relationship between the inflammatory periodontal disease and saliva is one evidence that oral fluid contains markers relevant to whole-body health.
Inflammatory markers are the tip of the iceberg. Saliva contains a vast array of biomarkers stretching far beyond oral health. The saliva of patients then, can be a valuable treatment tool. The health markers within saliva can be used to detect and track the progression of certain conditions and diseases. These include inflammation, cancer, cardiovascular disease, and hormonal imbalances.
Saliva-based biomarkers present a valuable predictive and diagnostic tool. Systemic diseases, diet, emotions, and hormonal shifts are all reflected in salivary secretions. These shifts occur quickly. As highlighted in a meta-analysis, dozens of factors shape saliva composition and amount. These include stress, sleep, diet, and even medications. Salivary levels of certain health markers, then, are a helpful tool for early diagnosis and detection, as well as tracking disease progression and efficacy of treatment.
As with the inflammatory periodontal disease, saliva can test for systemic inflammation. Saliva has a high detectable level of inflammatory markers. A comprehensive review showed that saliva has a unique function for measuring inflammation, particularly through its c-reactive protein biomarker.
C-reactive proteins (CRP) promote the production of pro-inflammatory cytokines. The presence of CRP alongside certain cytokines reflects levels of systemic inflammation. As salivary markers can detect inflammation through these pathways, saliva panels are helpful for detecting a host of neurological and infectious diseases.
Likewise, certain markers in saliva may be used to detect cancer. Cytokines such as interleukin-1, interleukin-6, and interleukin-8 are all measurable in the saliva. Proinflammatory tumor necrosis factor-alpha (TNF-α) is also a salivary biomarker. These cytokines, and, in particular, interleukin-8, are related to tumor progression and metastasis. Similarly, salivary levels of certain growth factors can indicate the presence of cancer.
Saliva testing is not limited to oral cancers. Alongside cancers such as oral squamous cell carcinoma, the molecular markers found in saliva can test for breast cancer and HIV. Emerging evidence shows that saliva may even contain markers for early-stage cancer.
Partly due to the prevalence of inflammatory markers in saliva, saliva can also inform heart health. In particular, c-reactive protein levels relate directly to heart health. Saliva testing for CRP levels may serve as a screening for cardiovascular disease risk. A 2021 systematic review showed high detectable levels of inflammatory markers in saliva.
Another salivary marker connected to periodontal disease, MMP-8, is connected to the pathogenesis of coronary artery disease. Additional non-inflammatory salivary markers are related to heart health. Endothelin peptides may be measured in the saliva. Endothelin peptides are directly related to blood pressure and heart disease.
Salivary diagnostics are particularly helpful for hormonal health readings. Salivary concentrations of hormones indicate the bioactive hormone levels. Dozens of hormones may be accurately measured in a single saliva panel, including cortisol, progesterone, estradiol, melatonin, DHT, and DHEA.
Saliva composition changes quickly. Therefore, saliva is a valuable tool for tracking hormonal changes over time. For example, saliva will reflect the shift of cortisol over the course of several hours, or the hormonal transition of a menstrual cycle.
Saliva testing provides biochemical data at a microscopic level. Decades of research have proven the validity of saliva testing as well as its convenience and accessibility. Saliva collection is simple and cost-effective, and a single salivary sample can provide extensive data.
Access Medical Labs is at the forefront of saliva testing with an industry-leading turnaround time. Our customizable saliva panels return results within 48 hours. Explore our NextGen Saliva panels.