About Saliva Testing
Saliva testing has many advantages over blood testing. Saliva specimen collection does not require a blood draw and there are no risks to patients. Saliva collections are convenient and can be done at work or at home. When stored properly, saliva samples are stable for several weeks.
With an accuracy of 92-96%, saliva testing is more accurate than blood testing. The ability to collect more than one specimen is another advantage of saliva testing because this can give providers more information than a single collection. Compared to blood testing, saliva testing is also more affordable.
The method of testing saliva that Diagnos-Techs, Inc. uses is called ELISA testing. For more in-depth information about this kind of testing please see Why Saliva?/Saliva Testing at a Glance.
There are several different ways of measuring the hormones in a person’s body. Most blood and serum tests look only at the level of hormones that are present in a person’s tissues. This is known as “bound hormone levels”.
Saliva testing looks at the “unbound hormone levels” also known as “free fraction hormone levels” which are the hormone levels that are available to be used by the body’s tissues. This gives providers a better idea of the levels of hormones that are actually influencing the tissues, rather than just the level of hormones that are present in the tissues.
Measuring free fraction hormone levels gives a provider more information than measuring bound hormone levels. Usually, when bound hormone levels are measured, a provider needs to guess at the level of hormones affecting the tissues. This is not the case when measuring free fraction hormone levels.
The accuracy of saliva testing, together with its affordability, convenience, and the ability to collect multiple specimens makes saliva testing superior to blood testing.
Advantages of Saliva Testing
• No blood draw is needed; no risk to the patient
• Specimens can be easily collected at home or at work at any time of the day
• Saliva measures the biologically active fraction of steroid hormone at the tissue level.
• Since hormone levels may vary during the day or during the month, multiple specimens can be collected conveniently offering precise measurement.
• Samples are stable for several weeks.
Saliva Testing At a Glance
All major steroid hormones, some peptide hormones, and antibodies can be readily detected and measured with reproducible results from a patient’s saliva.
Enzyme-linked immunosorbent assay (ELISA) is the most prevalent laboratory technique utilized in measuring various hormones, antigens, and antibodies within the saliva. The process involves using a prepared solution of antibody that is specific for a substance. The saliva sample is exposed to the solution that has the known antibody. If the substance tested for is present in the saliva, the antibody will bond to the substance and an enzyme linked chemical reaction will notify the scientist via a change in color. These test results may be designed to provide either qualitative (“positive vs. negative”) results or quantitative results (i.e. 5-50 nM/L, for example).
One of the profound advantages with saliva testing is that the saliva producing cells passively allow ONLY unbound steroid hormones into the salivary ducts. Therefore, saliva testing is a very affordable way to study active steroid hormone levels without the confounding artifact of having to separate the bound hormone from the unbound fraction.
It is this unbound hormone that exerts the activity that hormones are known for in various tissue beds throughout the body. If one is to measure total hormone levels in the blood serum, an extra step of mental extrapolation is required in order to try to predict how much of that total pool of hormone is actually having effects on a patient. Unfortunately, there is no predictable correlation between how much total hormone is in the blood serum and how much free hormone goes into the tissues and has a clinical effect on a patient.
Saliva testing specifically measures free, unbound hormone levels. This eliminates the need to make mental guesses concerning how much hormone a patient’s body is really being influenced by.
An additional, profound advantage of saliva testing is that it is non-invasive. If a substance can be identified and measured in the saliva, why submit a patient to venipuncture? In some clinical situations this may become necessary, but it is an unnecessary risk to take for an initial evaluation. Thousands of complications via venipuncture happen yearly and can result in transmission of blood born disease, puncture site inflammation and/or infection, pain, vein thrombosis, etc. Venipuncture is expensive, labor intensive, inconvenient, and carries the risk of adverse health outcomes.
In order to accurately study how hormones clinically affect a patient, it is necessary to look at hormone levels dynamically. In other words, hormone fluctuations are just as important as their level at any given one point in time. The practice of including a time component to the evaluation of a patient is called chronobiology. There are many well known chronobiological processes: sleep/wake cycles, seasonal mood changes, a woman’s monthly menstrual cycle, etc. It turns out that the adrenal glands are controlled by a daily cycle…as is the thyroid gland.
The hormones that influence many of the cycles in our lives can be viewed as markers to check if our body is in a healthy state from a standpoint of chronobiology. For example, multiple sample outpatient saliva testing allows a clinician to monitor the hormone regulation of a woman over her ENTIRE monthly cycle! This information can have profound diagnostic significance and can lead to therapeutic strategies over looked by one sample testing of her hormones.
In summary, enzyme linked laboratory analysis of the saliva has become scientifically accepted, clinically applicable, an excellent alternative to serum testing, the only way to reasonably study a patient’s chronobiology, and economically feasible.
If you are interested in more information regarding saliva testing, please see http://en.wikipedia.org/wiki/Saliva_testing