Among ancient peoples, it is said, this precious bodily fluid was used as the basis of a primitive lie detector test. The accused would be given a handful of rice and told to swallow it; if he couldn’t, it meant he was nervous – and guilty.
This slippery stuff also helps moisten and digest food, and has healing powers as well – proteins that fight bacteria, fungi and viruses and others that speed tissue healing, says Dr. Irwin Mandel, professor emeritus at Columbia University. In fact, animals that lick their wounds heal faster than those who don’t.
The fluid in question, of course, is saliva, or actually, spit – a combination of the saliva pumped out by salivary glands and all the other effluvia floating around in our drool: drugs (licit and otherwise), bugs (viruses, fungi, bacteria), hormones, antibodies and anything else small enough to seep out through tiny blood vessels into the mouth.
As unpleasant as it all sounds, spit is in. In fact, it could be the diagnostic fluid of the future, according to scientists who plan to gather next week at the National Institute of Dental and Craniofacial Research to explore spit’s many wonders – and economic potential.
Already, a number of companies are using the Internet to tout spit test kits, some of which have not been approved by the US Food and Drug Administration, which acknowledged last week it’s scrambling to keep up.
With the kits, consumers muster a little spittle, fork over $60 or so and send the sample to a lab to find out whether, say, their testosterone is tanking, their estrogen slipping, or their stress hormones soaring.
Spit, or more elegantly, oral fluid, is almost identical to the clear part of blood, but with everything – including infectious organisms – present in weaker concentrations. In the past, diagnostic tests were not sensitive enough to detect these low concentrations, but now they are.
That means that almost anything that can be detected in blood can theoretically be found in spit, too – with less pain, risk of infection and expense.
Spit testing is cheap because it’s so safe – neither patient nor health care worker can get stuck with a needle. “You don’t need a technician to get the sample,” says Dr. Stephen Sonis , chief of oral medicine at Boston’s Brigham and Women’s Hospital.
So far, spit tests have only been FDA-approved for a few limited uses – to detect the AIDS virus, illegal drugs, alcohol, a hormone that signals premature labor, and periodontal disease. There are no tests that allow a person to both collect and analyze spit at home – yet.
With the OraSure kit made by the Epitope Corporation of Beaverton, Ore., for instance, you have to go to a health care professional, who puts a toothbrush-like swab between your cheek and gums for a few minutes, then sends the sample to a lab to be tested for HIV. Insurers also use the OraSure kit to test for marijuana, cocaine, opiates or methamphetamines.
In other countries, the kit is used to collect spit for testing for hepatitis B and other diseases. And soon, this kit and others like it could be used to get DNA for testing from prisoners on parole or people at risk for genetic diseases. (It’s unlikely, by the way, that spit samples could be collected surreptitiously from, say, a coffee cup or eating utensil, because the sample would be too small and would degrade quickly without preservation.)
But as spit collecting and preservation techniques evolve, do-it-yourself spit tests could be commonplace.
Already, doctors use spit tests to monitor hormonal changes in infertile women, says Dr. Philip Fox, former clinical director at the National Institute of Dental and Craniofacial Research at NIH and now research and development director at Amarillo Biosciences Inc., in Amarillo, Tex.
Similarly, SalEst , made by Biex, Inc. in Dublin, Ca. allows women at risk of premature labor to have their spit tested by a doctor for the hormone estriol. If estriol rises before 36 weeks of pregnancy, it’s a signal the woman may go into labor prematurely.
But it is the gray area of spit testing through companies on the Web that concerns the FDA, which worries about consumers putting their trust in diagnostic tests that have not been approved.
The Great Smokies Diagnostic Laboratory in Ashville, N.C., for instance, offers spit tests for a number of hormones through its website (www.bodybalance.com). You pick the test – StressCheck, MaleCheck or FemaleCheck – pay $60 and send in your sample to see if your hormones are in the normal range. No doctors are involved.
The company claims the tests are “screening” tools, not true diagnostic tests, and admits its tests are not approved by the FDA. After inquiries from the Globe, the FDA said it is “concerned about the Great Smokies advertising and promotion as well as about other firms that advertise and promote lab tests on the web.”
While it is not illegal for labs to set up an in-house testing service and offer it through health care professionals, it is illegal is to offer this service directly to consumers, says Dr. Steven Gutman , director of the FDA’s division of clinical laboratory devices.
But “the beauty of the test” for consumers, argues Dr. Alison Levitt, a physician at Great Smokies, is precisely that “you don’t need to go to the doctor. . .People are interested in their hormone levels. People want numbers.”
Aeron LifeCycles Clinical Laboratory in San Leandro, California used to offer spit tests directly to consumers, too.
But last year, after federal and state regulators reviewed the lab’s practices, the company decided to put doctors in the loop, though you still don’t need to actually talk to a doctor to be tested, notes George Romero, customer service manager.
You simply send in your spit and $44, pick a name off a company-supplied list of doctors and that doctor signs the test order. For an additional fee, that doctor will help interpret the results, which you also get sent directly.
But how useful is it to send off some spit and get a few numbers that you try to interpret? Probably not very – in part because some hormone levels fluctuate wildly.
To test for stress, for instance, the Great Smokies lab checks levels of two hormones, DHEA (dehydroepiandrosterone) and cortisol. But cortisol levels vary over a 24-hour cycle, so if you send in only two samples a day, as the company website suggests, the potential for misinterpretation would appear to be high. In the version of the stress test sold to doctors, hormones are measured four times a day, says Great Smokies physician Levitt.
For researchers, however, it is precisely this variability in hormone levels that makes spit-tests a gold mine because they can track physiological changes almost in real time.
“When cortisol goes up in the blood, we find it in saliva within 20 minutes,” says Douglas Granger, a Pennsylvania State University behavioral endocrinologist. In studies of people before and after roller coaster rides, cortisol in saliva shoots up within 15 minutes, then returns to normal in an hour.
In other work, Granger has found similar cortisol spikes in kids experiencing family stress.
In one test, he asked mothers and kids to discuss a topic about which they disagreed, then had the kids spit into little cups. The kids judged the most anxious by other tests showed the highest rises in cortisol levels, says Granger, who has formed a research company to study spit for a number of hormones..
Ultimately, with more sophisticated spit kits, consumers could test their oral fluids at home. What spit testing offers, says, Dr. Irwin Mandel, affectionately known among researchers as “the grandfather of spit,” is “a lick and a promise” – a simple, reliable way of monitoring health.
Take care in getting tested
If you decide to have your oral fluids tested, especially by one of the services offered on line, be wary:
- When collecting the spit sample, follow package directions carefully. Typically, spit samples must be preserved quickly to remain useful. (For instance, if you’ve just eaten or drunk something, rinse your mouth and wait a few minutes before collecting spit.)
- Think about potential confidentiality problems. Anytime you reveal medical information on the Internet or send bodily fluids through the mail, your confidentiality may be at risk.
- Remember that a number of medical treatments and conditions, including drugs, radiation therapy, autoimmune problems such as Sjogren’s syndrome, can affect saliva. This could influence the accuracy of your tests.
- Most important, if you bypass a doctor and use the Internet to find a spit test service on your own, you could be jeopardizing your health. If you’re sick – or worried that you might be – call a doctor.