The promise of diagnosing illness through a simple saliva test is gaining momentum, offering a less invasive alternative to traditional blood draws. While currently limited in scope, advancements are paving the way for potential applications ranging from detecting viral infections to identifying early signs of cancer.
Currently, FDA-approved salivary diagnostic tests are primarily limited to detecting conditions like HIV and COVID-19. However, researchers are exploring the potential to use saliva to assess genetic risks for diseases such as breast cancer, diabetes, and even prostate cancer. The appeal lies in the ease of collection – a few drops of spit – compared to the more complex process of obtaining blood samples.
“It would be great to treat on a preventative basis rather than on a reactive basis,” says Wallace Bellamy, a dentist in Sacramento, California, and president of the National Dental Association. He envisions a future where salivary tests become a routine part of dental care, enabling earlier disease detection and potentially saving both lives and money. However, cost and insurance coverage remain significant hurdles to widespread adoption.
Currently, at-home or in-dentist salivary tests typically range in price from $100 to $200, with samples mailed to a specialized laboratory for analysis. Insurance coverage for these tests is currently limited, a major concern for many patients. “Most of our patients want to know if it’s covered by insurance, and it’s not,” Bellamy notes.
Detecting Disease with Saliva: Current Capabilities
Saliva’s diagnostic potential stems from its rich microbial content, offering a “microbial fingerprint” of an individual’s overall health. Researchers are finding that changes in salivary composition can signal the presence of disease. The tests can be accurate in detecting conditions like cavities and oral cancer, though these tests often lack full FDA approval.
Many companies offering these tests, like OrisDX, a Chicago-based company, operate without full FDA approval, relying on reliability studies conducted by the company itself. OrisDX plans to begin selling a test in April that detects squamous cell head and neck cancers with a reported 93% reliability. Samples are collected either in a dentist’s office or through dental telehealth and sent to a designated lab for processing. The company’s CEO, Harald Steltzer, emphasizes the unmet need for improved early detection methods, stating that current methods often rely on visual inspection, a practice unchanged for a century.
The process of obtaining FDA approval is rigorous, requiring exhaustive reliability studies. However, a recent change in federal spending legislation may incentivize companies to pursue this path.
New Incentives for FDA Approval
As part of its recent spending bill, Congress mandated that Medicare cover FDA-approved multicancer detection tests, regardless of whether they utilize blood, saliva, or other methods. Sheila Walcoff, a regulatory consultant and CEO of Goldbug Strategies, explains that this decision creates a significant financial incentive for companies to invest in obtaining full FDA approval. “Now that there’s a carrot out there that they can get immediate national reimbursement for those tests, then that’s really going to push them forward,” she says.
Challenges and Future Directions
Despite the promising advancements, several challenges remain. Saliva’s composition is dynamic, influenced by factors like brushing, eating, drinking, and smoking. This variability makes it more difficult to analyze than blood, according to Purnima Kumar, chair of periodontics and oral health at the University of Michigan and a spokesperson for the American Dental Association. “There’s a lot of variability,” Kumar explains. “They’re like a microbial fingerprint for you.”
Researchers are actively working to identify specific salivary markers that can reliably indicate disease across diverse populations. Kumar anticipates that, if successful, salivary testing will help lower barriers to healthcare access. She currently uses at-home saliva tests in her practice to monitor for infection following oral surgery, particularly for patients in rural areas or those with limited transportation options.
It’s important to note that salivary tests are not intended to replace traditional in-person medical care or dental visits. Rather, they could serve as an additional tool for monitoring health, similar to how blood tests are used to assess cholesterol or liver function. As Kumar describes it, salivary tests could act as a “health alert system,” prompting individuals to seek further medical attention when necessary.
Recent research, published in , highlights the role of salivary diagnostics in the early detection of both systemic and oral diseases. A report in the Journal of Molecular Diagnostics details the use of acoustofluidics, a non-invasive method, to analyze saliva for the presence of human papilloma virus (HPV)-16, associated with oropharyngeal cancers. This technique detected HPV in 40% of patients tested and 80% of confirmed cases.
