Cortisol in saliva | Laboratory study

General Information

• Each test means one tube for collecting the sample!
• If a patient needs multiple samples, they pay for each tube separately!

Samples are shipped every Friday!

The material must be submitted to the regional laboratory center on Thursday, in the first half of the day, and to the Tbilisi branches on Thursday throughout the day, or on Friday in the first half of the day!

Cortisol is an important glucocorticoid that is involved in the regulation of a number of physiological processes. Cortisol is synthesized in the adrenal cortex. 90% of cortisol in the bloodstream is bound to steroid-binding globulin and the protein albumin. Only a small fraction of it circulates freely, interacting with receptors.

In addition to its anti-inflammatory and immunosuppressive properties, cortisol increases blood glucose concentrations by stimulating gluconeogenesis.

The synthesis and secretion of cortisol are regulated by the hypothalamic-pituitary-adrenal axis through a negative feedback mechanism. Low levels of cortisol in the blood cause the hypothalamus to secrete corticosterone-releasing hormone, which stimulates the pituitary gland to produce adrenocorticotropic hormone. Adrenocorticotropic hormone, in turn, affects the cells of the adrenal cortex, where cortisol is synthesized. Stress also stimulates the secretion of cortisol.

Cortisol levels change throughout the day – they are higher in the morning and lower in the evening.

Cortisol in saliva

The concentration of free cortisol in serum is in equilibrium with the concentration of salivary cortisol.

The sensitivity of the saliva cortisol test is 92-100% and the specificity is 93-100%.

Salivary cortisol measurement is an important test for diagnosing Cushing's syndrome and evaluating the effectiveness of treatment, including in children.

Returning salivary cortisol levels to normal is directly related to a reduction in hypertension, hypokalemia, and psychiatric symptoms. Salivary cortisol levels can be used to predict postoperative outcomes and potential recurrence of pituitary adenoma.

When is the survey conducted?

• Determination of cortisol in saliva is the first-line test in the diagnostics of Cushing's syndrome.
• The test is administered to patients with obesity, depression, type 2 diabetes, arterial hypertension, menstrual disorders, and secondary osteoporosis.
• The test is performed on patients with age-inappropriate conditions: such as premature hypertension, osteoporosis, and others.
• In overweight children, with growth retardation
• In patients with adrenal incidentalomas
• In patients who have multiple clinical manifestations on the background of cortisol excess.

Patient preparation

Before collecting a sample, it is necessary to consider several recommendations:

• Smoking is not permitted on the day of sample collection.
• It is not allowed to brush your teeth immediately before collecting the sample.
• Food and drink are prohibited for 30 minutes before sample collection.
• It is recommended to stay in a relaxed state for 3 hours before collecting the sample (to avoid physical and emotional stress).
• It is optimal to take the sample between 11:00 PM and 12:00 AM.

• One test tube is intended for each study.
• If it is necessary to take several samples, a separate study is created for each sample, with an appropriate tube and an independent code.
• We take the patient home with a sample collection tube.

Before collecting a sample, it is essential to follow patient preparation recommendations to avoid sample contamination and inaccurate results.

It is recommended to collect cortisol in saliva between 11:00 and 12:00 at night, in a resting state. At this time, cortisol levels are minimal and it is against this background that its level should be determined to detect a violation. However, based on the doctor's instructions, a sample (saliva) may be collected at other times of the day.

If multiple samples need to be taken as recommended by your doctor, each will be collected in a separate tube and individually coded in the laboratory.

If multiple cortisol samples are needed during the day, samples should be taken at the following times:

From 06:00 to 10:00 (morning)

From 16:00 to 20:00 (evening)

Between 23:00-24:00 (midnight)

Sample collection instructions

1. Open the sample collection tube (do not touch the swab in the tube with your hands)

2. Place the swab on your tongue by applying pressure to the tube.

3. Gently rotate the swab placed on the tongue into the epiglottis and moisten it with saliva.

4. Without touching it with your hands, return the tampon to the tube.

5. Fit the lid to the tube. Indicate the time of sample collection (date, time) on the label.

6. Store the sample in the refrigerator until delivery to the laboratory (at a temperature of 2-8 degrees Celsius).

Sample processing

• Centrifuge the tube received in the laboratory for 2 minutes at 3000 rpm.
• After centrifugation, remove the swab from the tube.

Sample volume: 1 ml

Stability: 4 days at 2-8 degrees. Frozen 12 months

Method: ECLIA immunoassay, with electrochemiluminescence

Interpretation of results

Cushing's syndrome is characterized by elevated salivary cortisol levels.

When detecting elevated salivary cortisol levels, it is recommended to repeat the test at least 2 times (on different days).

The results of the study are affected by the presence of concomitant diseases, disruption of the circadian rhythm (when working in shifts), contamination of the sample with oral gels containing steroids (gives a false positive result), collection of the sample at the wrong time of day (a sample collected in the morning is often useless).

• Each test requires one sample collection tube!
• If a patient needs multiple samples, they pay for each tube separately!