Saliva diagnostics for measuring steroid hormone activity in a number of different endocrine disorders or even checking the correct hormone balance and endocrine function is fast becoming one of the most convenient and reliable method of choice. This measurement was traditionally performed using samples of blood, serum or plasma, however, now many hormones are analysed using saliva. As a result of this it is now possible to investigate many new diagnostic strategies which could not have been contemplated using blood, plasma and serum samples.
Saliva samples offers many advantages
- Specific analysis of either the biologically active or the “free” fraction of the target hormone is now possible.
- Sample collection process is non-invasive, does not require any specially trained medical staff and provides no significant discomfort to the patient.
- Samples can be collected at home, at work, during physical exercise or whilst travelling.
- It is so simple to perform, even patients such as elderly and children can manage it themselves.
- Multiple specimens can also be collected, anywhere and at any-time.
SALIVARY DIAGNOSTICS APPLICATIONS
Currently, there is growing evidence that the most reliable method for steroid hormone testing is saliva samples. It has quickly become the specimen of choice in many traditional care situations, health measurement and monitoring because of the many benefits it offers over using blood samples. Also, it offers the advantage of being able to evaluate a pooled saliva sample taken from multiple collections that can help to minimise any diurnal fluctuations.
The determination of free steroids using saliva is particularly helpful in the following diagnostic applications: endocrinology, neuroendocrinology, immunology, psychology, anti-aging, sports, fertility testing, HRT monitoring and veterinary medicine. Some of these application have be discussed in more detail below.
- Endocrinology: Deals with the endocrine system, its diseases and specific secreted products which are referred to as “hormones”.
- Androgen status: measuring free testosterone is a well-known diagnostic tool which is routinely used to determine the androgen levels in both women and men. Saliva samples allow direct measurement of only the free, biologically active fraction which is not possible using the conventional serum immunoassay methods. There is evidence to indicate that the free salivary testosterone levels present in the morning samples correlate with the calculated free testosterone in blood, for healthy men and androgen deficiency patients.
- Cushing’s syndrome: a disease that is characterised by the failure to reach circadian nadir in the secretion of cortisol late at night. It is caused by the excessive secretion of adrenocortical hormones (mainly free cortisol). Late-night salivary cortisol screening is now a well-accepted and is highly recommended for Cushing’s syndrome patients.
- Sports Medicine: Monitoring the levels of various hormones during sport sessions can provide useful information in order for athletes to optimise their training programs. During physical exercise, free salivary cortisol, testosterone and DHEA concentrations are all elevated depending on the exercise intensity. In sport science it is important to be aware that hormone levels and exercise-induced hormone changes vary among subjects depending on the different types of training undertaken. Secretory IgA levels are also routinely measured in order to provide useful information regarding the athlete’s immune status.
- Anti-Aging Medicine: A correct hormonal balance is a key factor to good health, in particular free progesterone, testosterone and estradiol concentrations. For example, the determination of free testosterone levels is highly recommended for women that suffer virilisation and hirsutism, as well as male patients of primary and secondary hypogonadism. Hormone replacement therapies are known to be readily adjusted following results obtained from salivary hormone assessments.
- Psychology & Occupational Medicine: Area of research which covers behaviour and mental processes, including: cognitive psychology, biological psychology, social psychology and occupational health.
- Stress Research: Often in many cases relies on questionnaires, however, some common biological parameter which have been routinely used included measuring levels of free salivary cortisol and alpha-amylase.
- Sleep Disorders: Combined measurements of melatonin and cortisol concentration have been helpful in the evaluating the circadian rhythms of an individual. Melatonin is the key substance promoting night-time sleep and both of these hormones are regarded as stress markers.