A saliva ELISA for dehydroepiandrosterone (DHEA) analysis

The DHEA Saliva ELISA is meant for the quantitative measurement of the DHEA hormone using human saliva samples from adult patients. The DHEA hormone is discharged by the adrenal gland.

This test is meant for measuring DHEA levels as a physiological marker as an aid in the diagnosis and treatment of suspected abnormality of the adrenal gland, along with other clinical parameters, such as cortisol and other hormones.

Besides other clinical observations and diagnostic tests, the information is beneficial in assessing the level of adrenal function as proof of physiological status in aging adults.

  • Method — ELISA
  • Substrate/isotope — TMB 450 nm
  • Specimen/volumes — 50 µL saliva
  • Regulatory status — EU: CE
  • Incubation time — 1 x 2 hours, 1 x 30 minutes
  • Kit size — 12 x 8
  • Standard range — 20–2160 pg/mL

Measurement of DHEA levels along with other hormones has been proven to be beneficial in the assessment of hormone imbalance that leads to a range of clinical conditions such as hyperandrogenism (excess of androgen hormones), for example, polycystic ovary syndrome (PCOS). Using non-invasive sample types from saliva renders the test ideal for numerous sampling and testing of DHEA levels.

The DHEA Saliva ELISA cannot be used in the diagnosis and treatment of DHEA-secreting adrenal carcinomas. The DHEA Saliva ELISA is a solid phase enzyme-linked immunosorbent assay (ELISA), based on the norm of competitive binding and quantified on an absorbance reader.

The assay is semi-automated, necessitating general-purpose laboratory instruments and consumables such as vortexer, absorbance microplate reader/washer and pipettes to implement the test.

The assay can be adapted by laboratory personnel to automate on open ELISA-based liquid handler systems; however, the programming of the steps and timing needed by the manual kit assay test instructions must be stringently complied with and confirmed by the laboratory.

Test results can be computed manually from a standard curve and compared to laboratory-proven reference ranges from healthy adults (i.e. standard ranges). The test kit is meant for professional laboratory use by skilled personnel. The test kit must not be used at home or by a layperson.

The IBL International DHEA Saliva ELISA correlates excellently to the LC-MS/MS technique and provides definite reference values for men, women, age and time of day.

Advantages of the measurement of DHEA in saliva and for the IBL DHEA Saliva ELISA

  • Stress-free and non-invasive sampling where blood collection is either unwanted or problematic
  • Reflection of circulating level of free bioactive steroid fraction instead of total circulating levels, which are impaired by the presence of circulating binding proteins
  • Method comparison of the DHEA saliva ELISA to the LC-MS/MS; y = 0.91x – 13.35; r = 0.96; N = 130
  • Measuring range: from 8.7 pg/mL (LoQ) to 1516.3 pg/mL (Linear range)
  • The TMB, stop solution and wash solution have the same design within testosterone, cortisol and progesterone saliva ELISA (RE52631, RE52611 and RE52281)*

*Valid lot numbers of TMB, stop solution and wash solution are mentioned on the outer labels and Quality Control certificates of the kits.

The DHEA concentration of 140 saliva samples from seemingly healthy women and men (morning and evening samples) was quantified in the DHEA Saliva ELISA. The DHEA level drops in elderly women and men as well as in evening samples. Owing to the pulsatile dynamics of DHEA secretion, frequent saliva samples were examined.

Source: Tecan

A saliva ELISA for dehydroepiandrosterone (DHEA) analysis

A saliva ELISA for dehydroepiandrosterone (DHEA) analysis

Image Credit: Tecan

It is recommended for each laboratory to fix its own range of standard values. As many specific biases, like gender, age and the time of day, have to be taken into consideration, each laboratory should fix its own reference range keeping in mind the patient population.

To measure the adrenal working of a patient, it is essential to calculate a baseline DHEA value reliant on the individual or affected population and the time of day and equate it to a healthy control group population.

Several measurements are suggested to derive a patient’s profile. Measurement of DHEA levels along with other hormones has been demonstrated to be beneficial in the evaluation of hormone imbalance that leads to a range of clinical conditions such as hyperandrogenism (surplus of androgen hormones), for example, polycystic ovary syndrome (PCOS).

In the particular case of PCOS, the DHEA levels in salivary samples were recognized to be for hormone imbalance that leads to a range of clinical conditions such as polycystic ovary syndrome (PCOS, a type of hyperandrogenism) values of 390-690 pg/mL, with values up to 1190 pg/mL being detected.

As measurements of DHEA levels are a physiological marker in the analysis and treatment of suspected deficiencies of the adrenal gland, they have to be performed along with other clinical factors, like cortisol and other hormones, and the results should not be the only reason for any therapeutic significances.

DHEA must not be assumed to be the only parameter to look into for verifying a diagnostic, and as such, it is vital to include information from other adrenal hormones values for a full clinical diagnostic representation. Just the results alone must not be the only reason behind any therapeutical consequence. They have to be matched with other clinical studies and diagnostic tests.

Summary and explanation

DHEA (Dehydroepiandrosterone) and its sulfate ester DHEA-S, as C-19 steroid hormones, fall under the category of a group of androgens. The zona reticularis of the adrenal glands yields about 80% of DHEA, with the rest created by the ovaries, testes and brain. DHEA acts as a precursor in estrogen and testosterone synthesis. In blood, DHEA is loosely attached to SHBG and albumin.

Just a small portion of the hormone, about 5%, stays unbound and can enter the saliva via intracellular diffusion and ultrafiltration mechanisms, and thus, salivary concentrations reveal the concentration of serum.

DHEA level in saliva samples represents the circulating level of free bioactive steroid fraction in the body, instead of total circulating levels that are measured in blood, which are hindered by the presence of circulating binding proteins. DHEA levels reveal major diurnal variation, which is reliant on adrenocorticotrophic hormone (ACTH).

It has been demonstrated that DHEA exhibits a flat pattern of secretion upon waking, followed by a progressive drop to 3 hours post-awakening with no major change afterward. The standard DHEA concentration varies considerably with age.

The level of DHEA begins to rise at the adrenarche and reaches its highest level at the age of 20–30 years. After that, the adrenal creation of DHEA drops in both men and women, until concentrations of DHEA get back to pre-adrenarche levels in persons above the age of 80 years.

The DHEA Saliva ELISA assay is meant only for adult patients. Biochemical/physiological adult pattern can be attained already by age 14, at least for girls, and 16 years for boys.

There is proof that the declining level of DHEA and enlarged cortisol/DHEA ratio contribute to the immune and cognitive deficiencies in elderly people, as well as affect the ability of older people to carry out everyday tasks. Higher cortisol/DHEA ratios, instead of the hormone levels individually, have been related to immune deficiencies and infection risk in older adults exposed to chronic psychological and physical stress.

Acute Stress and Posttraumatic Stress Disorder are categorized by a higher level of DHEA than control groups because of heightened ACTH secretion triggered by stress and/or traumatic events. Testing DHEA in saliva proposes a stress-free and non-invasive sample collection technique, which helps avoid further stress burden on patients with psychiatric issues.

Using non-invasive sample types from saliva renders the test suitable for numerous sampling and testing of DHEA levels. The main laboratory findings that help a clinician to assess the HPA axis status in a person are total cortisol output, cortisol diurnal rhythm, cortisol awaking response, total DHEA(S) and cortisol/ DHEA ratio.

By itself, the measurement of DHEA levels in saliva, along with other clinical observations and diagnostic tests, is beneficial in measuring the level of adrenal function as a deduction of physiological status in aging adults.

Measuring DHEA levels is beneficial as an aid in the diagnosis and treatment of adrenal disorders along with measurements of other sex steroids such DHT, testosterone and androstenedione.

Acne, alopecia, hirsutism, oligo-amenorrhea and polycystic ovary syndrome (PCOS) are clinical expressions of hyperandrogenism. The usage of saliva offers a simple, sensitive, dependable and non-invasive diagnostic method to evaluate biochemical hyperandrogenemia.

Pulsatile dynamics

Owing to the pulsatile dynamics of DHEA secretion, repeated saliva sampling is suggested. It is recommended to take five samples within 2 hours after waking up. In the lab, equal quantities of specific saliva samples can be mixed. This mixed sample offers a mean free DHEA value, which signifies the active hormone concentration in a reproducible manner.