Ready, Set, Spit! Will Saliva Tests Replace Blood Tests?
It's hard to imagine how something that was once thought to be so obnoxious may now detect certain medical diseases much easier than blood or urine tests.
It’s hard to imagine how something that was once thought to be so obnoxious may now detect certain medical diseases much easier than blood or urine tests. Saliva tests have been around for a while, but recent clinical research has suggested that more advanced disease detection may also be accomplished by simply spitting into a cup. Although saliva test detection is already in use for HIV, hypogonadism, measles, and hepatitis, research is expanding into the realm of using it to detect breast cancer and head and neck cancers, among other diseases. In fact, a group of researchers at UCLA has been working to identify all 3,000 proteins that are found in saliva. They believe that by 2011 saliva tests “will take the place of routine blood tests and even do more, such as detect cancer at early stages.”
Saliva vs. Blood
Saliva tests are non invasive — the test results “may be more accurate in that less stress on the system during the production of the specimen means less interference with the factors being tested.”
Saliva tests are easier to obtain — no syringes, no scared patients.
Saliva tests are less painful — needles are not necessary, so patients don’t have to suffer from multiple stabs by a healthcare professionals trying to find a good vein.
Saliva tests are less expensive — a healthcare professional isn’t needed to extract the specimen
Now Spit!
Results were recently released from two groundbreaking studies conducted by the University of Texas (UT) Health Science Center in Houston and the Johns Hopkins Kimmel Cancer Center, which evaluated the efficiency and accuracy of a “spit test” to detect breast cancer and a “swish-and-spit” test to detect head and neck cancers, respectively.
The study from UT, led by Charles Streckfus, DDS, MA, FAAOM, FAGD, professor of diagnostic sciences at the UTHSC dental branch, “can identify and quantify specific proteins markers in human saliva to provide an early, non-invasive diagnosis of breast cancer.”
The results further demonstrated that dentists can go beyond providing care for a patient’s teeth; they can also test saliva for breast cancer, working with other healthcare professionals to “provide quick, accurate diagnostic information and physician referrals to their patients.” In conjunction with the McDevitt group, UT has been working to develop a testing device that would enable a dentist to analyze the saliva during a routine visit without any delays. Additional research is being conducted to determine whether saliva tests can detect ovarian, endometrial, cervical, and head and neck cancers.
Dr. Joseph Califano, MD, of the Johns Hopkins Kimmel Cancer Center, and fellow researchers conducted two-arm studies that required 211 patients with head and neck cancer and 527 healthy participants to gargle a salt solution after brushing and rinsing the inside of their mouths, as a way to determine if this type of cancer can be detected through this simple screening method. Based on the results, they learned that, although a blood test is more accurate, a saliva test may become a useful alternative. Dr. Califano also said that some head and neck tumors “do not shed genetic material into the blood, making the saliva test a better bet.”
A Hopeful Future
Although it appears that researchers are focused on developing spit tests to detect a person’s risk of developing cancer, the hope is to develop this type of test to detect type 2 diabetes, Alzheimer’s disease, and rheumatoid arthritis. Blood may have higher concentrations of biomarkers than saliva (1,000 to 10,000 times lower), but technological advances have allowed researchers to view saliva biomarkers using “instruments with sensitivity 1,000 to 10,000 higher than used for current blood samples.”
Additional Resources
Saliva Tests Detect Disease, Cavities and Drug Use
Simple Diagnostic Test Detects Genetic Signs of Lung Cancer in a Patient's Sputum
