Why saliva is an important biofluid for disease detection

Introduction

Saliva is a remarkable biofluid with clinical significance, and it’s gaining attention as a diagnostic specimen for early disease detection. Here are the main reasons:

Non-Invasive Collection

Saliva can be easily collected without the need for invasive procedures, making it more convenient than blood or urine samples.

Biomarkers

Saliva contains various biomarkers that can provide critical information about both oral and systemic health. These biomarkers range from proteins to non-coding RNAs (ncRNAs) and can be used for disease detection.

Point-of-Care (POC) Devices

Saliva-based tests are being explored for rapid tests and POC devices. They offer an economic and effective way to detect diseases, including COVID-19.

Low Cost

Saliva collection devices can be manufactured inexpensively and as consumer products.  The tests using saliva samples can be designed to be low cost and easy to use, such as lateral flow immunoassay, that don’t require handling by technicians, or require professional laboratories.

Home-based Collection

Specimen collection can be done in the privacy of one’s home then sent for further testing eliminating the need for subjects / patients to travel to clinics for testing then later in time for results

Transportation and Disposal

Saliva is much easier to transport than blood and can be disposed of in normal waste / drain rather than as biohazardous waste

Regulatory Approvals

Saliva as a biofluid with the potential for disease diagnosis has been receiving FDA attention from as early as the 1990’s.  Below are some of the FDA approvals of saliva collection devices.

Disease Detection

Saliva has been approved by FDA and EU authorities for the detection of certain diseases or for other purposes.

Other Purposes

EU Approval

Saliva-based diagnostics have shown promise in detecting various other diseases. Here are some examples of diseases under investigation:

Oral Diseases

• Periodontal Disease: Saliva contains biomarkers related to gum health, aiding in early detection of periodontal disease.
• Oral Cancer: Certain proteins and genetic markers in saliva can indicate oral cancer risk.

Systemic Diseases

• Diabetes: Levels of various salivary biomarkers correlate with blood glucose levels, making these biomarkers useful for monitoring diabetes.
• Autoimmune Diseases: Saliva biomarkers may help diagnose conditions like Sjögren’s syndrome and systemic lupus erythematosus.
• Cardiovascular Diseases: Some studies explore saliva markers for heart disease risk assessment.

Infectious Diseases

Hepatitis B and C: Saliva-based tests are being researched for these viral infections.

Drugs of Abuse

There are many saliva drugs of abuse tests that detect marijuana [THC] and other abused drugs. Saliva is actually a better indicator of impairment in subjects over the limit for THC

General Wellness/ Women’s Health

Various hormones in saliva are used to provide an indication of overall wellness and for women’s health issues. Hormones in saliva are present in the “non-complexed” forms whereas in blood the hormone molecules are “complexed”. As a result salivary hormones reflect the true values.

In Summary

Saliva’s ease of collection, cost-effectiveness, and potential as a diagnostic medium make it an exciting area of research for detecting systemic diseases. While challenges remain, ongoing studies continue to explore its usefulness as a diagnostic tool.