Saliva sample testing is a technique used to collect samples of a person's saliva, or spit, to check for or monitor certain drugs, hormones (chemical messengers from one cell or group of cells to another), antibodies (substances in the body's blood or fluids that act against such foreign substances as bacteria), and other molecules present in the body. With a saliva sample, diagnostic data for such diseases or conditions as human immunodeficiency virus (HIV), hypogonadism (reduced or absent secretion of hormones from the sex glands, the gonads), measles, hepatitis (a liver disease caused by the hepatitis A virus), certain cancers, low fertility, menopause and others are available without having to draw a person's blood. Saliva can reveal use of alcohol and many drugs. With simple use-at-home kits, women can self-determine when they are ovulating, which is especially useful when trying to conceive a child. Researchers also have found they can detect stress in a person through saliva samples.
Origins
In ancient times, saliva served as "judge and jury" when a person was accused of a wrong-doing. The suspect was given a mouthful of dry rice; and if his anxiety reduced saliva flow to the point that he could not swallow the rice, he was considered guilty as charged. To this day, a dry mouth signals nervousness. Spittoons were common in history until it was discovered that saliva carries germs.
Scientists began to realize that along with germs, saliva carries clues about our bodies. Saliva contains important enzymes (organic substances that accelerate chemical changes) that help digest food, and this natural body fluid serves as an antimicrobial, fighting viruses and diseases that enter our bodies. Additional properties in saliva help fight off bacteria.
In the twentieth century, researchers learned that saliva reveals to the presence of diseases and conditions that once were monitored only by measuring blood, urine, or other fluids. For example, a Spanish gynecologist named Biel Cassals, M.D., noticed in 1969 that saliva would "fern," or crystallize during hormonal changes, almost identically to the changes observable in cervical mucus. These changes in cervical mucus have helped predict when a woman is about to ovulate. Further studies of salivary ferning through the 1990s showed that saliva also could also help predict ovulation (when an egg is released from an ovary in response to a hormonal signal) with a high degree of accuracy. By the twentieth-first century, at-home kits using saliva to help women trying to conceive children were introduced and marketed.
Since the 1980s, some nutritional practitioners have used saliva samples to measure certain imbalances and disease processes in order to determine a person's need for a nutritional plan and dietary supplements. In addition to hormones related to ovulation, some physicians and other practitioners have measured other hormone levels in saliva, including testosterone, cortisol, and melatonin. Melatonin levels are much higher at night than in the daytime. Sometimes supplements are suggested for people who have trouble sleeping.
By 2004, more and more uses for saliva sample testing were in experimental stages or being approved by the U.S. Food and Drug Administration (FDA). In fact, saliva research has led to many important discoveries. Saliva holds a complete imprint of a person's DNA, or genetic makeup. In effect, saliva once again serves as judge and jury, since a crime laboratory can determine who committed a crime, based on the saliva left after licking an envelope seal, for example. Saliva tests are increasingly being used to test people for the presence of drugs and alcohol and may one day be used to test them immediately after being pulled over or at police checkpoints.
Benefits
Such laboratory tests as saliva sample tests are used to help a person detect a disease or other condition. Saliva sample testing is particularly beneficial because it is less invasive or noninvasive. Noninvasive means the skin does not have to be broken or an organ or cavity of that the body entered. As a result, 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. In some cases, a swab is put in the mouth to collect the saliva or sufficient quantities of saliva, are gathered by spitting for several minutes into a collecting tube, but studies have shown that many patients prefer this collection method to being pricked in the arm or finger with a needle. Health care workers say saliva samples are much easier to obtain, especially from children.
Saliva sample tests offer other benefits as well, depending on the specific test and its use. The saliva test for HIV provides results in about 20 minutes while the person waits at the testing facility. In the past, people having HIV tests had to wait for days or weeks to learn results and often did not return. Another major benefit of oral HIV tests is that they can reduce transmission of HIV to health-care workers, who once had to worry about accidentally pricking themselves with the needle they had used to test an HIV-infected patient. Those who test for HIV with saliva kits will not have to worry about handling blood. No cases of HIV transmission through saliva have been documented. The HIV sample test's noninvasive nature and rapid results may even lead to increased screening, especially among young people. The ease and rapid results could make the test valuable in Africa and other countries with widespread need for testing.
Finding less invasive methods to test for a number of diseases is a benefit for many people. Research has been done on a saliva test to detect a person's immune response to the anthraxvaccine, in the event of a bioterror attack, which would help emergency workers rapidly determine who has been immunized and who has not without having to gain access to their medical records.
At-home kits that use saliva instead of urine to help determine ovulation have made it more convenient for women trying to conceive children to track their hormonal cycles, eliminating a lot of guesswork. Instead of simply predicting ovulation, the new saliva-based tests more precisely indicate the timing of ovulation. They also allow women to save results from previous months and compare cycles to determine patterns. The tests are reportedly accurate up to 98% for timing of ovulation.
Saliva sampling is also a more accurate way of measuring a woman's hormone levels, pre-, peri-, and post-meno-pause, for fertility studies and hormone replacement therapy. The reproductive hormones of estrogen and progesterone weave a complex pattern throughout the length of a woman's cycle. For women who are still menstroating, a blood test for hormone levels reveals only a single snapshot of this very complex pattern, whereas the saliva sampling, done throughout the cycle, reveals the relationships and balance of the hormones. For women who are no longer menstruating, saliva sampling is able to quantify and qualify the amounts and rates of hormone level changes, and may reveal that a woman's symptoms, for example, are a result of low progesterone rather than low estrogen. Saliva sampling may be used as a very effective diagnostic tool in helping a woman balance her hormone levels, thereby guiding the aging process to a more fluid, and graceful adjustment over time.
Description
In most cases, the saliva sample test works by using a plastic stick with a pad on the end to swab or rub against the patient's gums to gather saliva. Other tests work by simply inserting a foam pad on a stick into the person's mouth, having the person pucker his or her lips, and moving the pad slightly around for a period of time until enough saliva fluid has been gathered. Still others rely on asking the patient to spit directly into a collecting container.
The collected saliva then is exposed to a reagent, a chemical substance that is known to react a certain way, to indicate a positive result or measures ranges. For instance, the pad from an HIV saliva collection is put in a vial of reagent solution. Within 20 minutes, certain colored lines may appear, indicating a positive result. Other samples may be collected at home, mailed to a laboratory, and may take longer to be analyzed and reported back.
Women who test at home for ovulation will place a drop of saliva onto the device, let it dry and look through a dial that magnifies and lights up the sample for about 45 seconds.
Preparation
Preparation may depend on the use of the test. It is best to follow any instructions given by laboratory personnel or on a home test kit package. For some saliva tests, it is recommended that the person have nothing in his or her mouth for at least five minutes before sample collection. Certain foods may need to be avoided for a period of time prior to testing. These foods are indicated in the instructions. One such set of instructions advises the avoidance of eating, drinking and brushing the teeth for a minimum of 60 minutes prior to collection. If sublingual (under the tongue) hormone drops are being used, a person will need to wait until after collecting the saliva before taking the drops. Saliva sampling may not be accurate or useful if a person has gingivitis, or gum disease.
Precautions
If a person has a condition such as Sjögren's syndrome, which causes dry mouth and poor saliva production, he or she may not be a candidate for saliva sample testing. Certain medications also can cause a dry mouth.
When using at-home ovulation saliva test kits, women must remember not to use them to help prevent pregnancy. The kits are not designed for that purpose. Smoking, eating, drinking, and brushing the teeth can affect test results, as can the way in which the person puts saliva on the slide. Further, any home test kit is not intended or recommended to take the place of periodic visits to a physician or other health professional.
Some medical professionals involved in HIV prevention have expressed concerns about saliva sampling for HIV, including an unintended effect of making the general population wrongly believe that HIV can be spread through saliva. Others have been concerned that the ease of saliva testing could lead to abuses, with authorities testing without first obtaining the person's consent.
Caution should be used when having saliva sample tests for nutritional measurements. It is best to check with a registered alternative medicine practitioner or licensed physician before paying for at-home saliva tests for this purpose. Some saliva sample tests will be completed at medical offices or sent to laboratory facilities. Those done at home should be completed with kits approved by the FDA or by a professional healthcare provider.
Side effects
There are no known side effects to saliva sample testing.
Research & general acceptance
In March 2004, the FDA approved saliva sample testing for HIV. Home-based test kits have been approved by the FDA for use in determining ovulation. Many other tests were under constant experimentation or in the approval process throughout the early twenty-first century. Manufacturers must go through an exhaustive process of clinical trials and application with the FDA before marketing these types of products to the public.
Training & certification
The Clinical Laboratory Improvement Amendments (CLIA) passed by Congress in 1988 and finalized in 1992, regulate clinical laboratories in the United States, including education and training of laboratory personnel. Generally, test samples are processed by medical laboratory technicians (MLTs) or clinical laboratory technicians (CLTs). They usually have an associate degree and have completed an accredited program for technicians. The technicians are supervised by other laboratory professionals with more advanced scientific training. Technologists with special training reviewing results under microscopes or preparing tissue samples to diagnose disease also will handle a sample, depending on the type of test involved. A laboratory director oversees the operation. He or she usually is a physician (an M.D. or, as allowed in some states, an N.D.) or scientist holding a doctorate (Ph.D.) with training in interpreting disease via cell samples. Often, the physician is a board-certified pathologist.
PERIODICALS
Berger, Abi. "Saliva Test Could Diagnose Cancers." British Medical Journal (March 25, 2000): 825.
"FDA Approves Oral HIV Rapid Saliva Test 99 Percent Accuracy Results in 20 Minutes." British Medical News Today (March 27, 2004).
"Oral HIV Testing Can Increase Belief in Disease Transmission Through Saliva." Biotech Week (September 10, 2003): 229.
"Saliva-Based Rapid Test Kit Hits Market." Medical Devices & Surgical Technology Week (September 23, 2001).
Young, Karen. "FDA Clears New Saliva-Based Test for Determining Ovulation." Diagnostics & Imaging Week (August 14, 2003): 3–4.
ORGANIZATIONS
U.S. Food and Drug Administration Office of In Vitro Diagnostic Device Evaluation and Safety. HFZ-440 2098 Gaither Road, Rockville, MD 20850. (301) 594-3084. <http://www.fda.gov/cdrh/oivd>.
