A Smartphone Cortisol Test

A quick, easy and inexpensive test for testing cortisol should soon be available on all smartphones or smartphone cortisol tests.

Researchers have developed a device that uses a smartphone to measure the concentration of cortisol in saliva. This new process was presented at the congress of the International Society of Endocrinology in Chicago.

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Cortisol is a hormone made by the adrenal glands that are essential for the body’s response to stress. Measuring this level can help diagnose adrenal gland diseases and monitor stress levels. Today to know the cortisol levels of a patient, it is necessary to collect a sample of saliva and send it to a laboratory for clinical analysis.

smartphone cortisol test


The person being tested inserts a saliva collector like a straw under their tongue. The collector drains saliva by capillary action (like a blotter that sucks up ink) to an immunoassay strip housed in a cassette and the cassette is inserted into a reader. The smartphone uses its camera and flash to take a picture of the saliva strip. It produces an algorithm that converts the pixel density of the image to a cortisol value.

“We have developed a method for measuring cortisol in saliva using a smartphone and a disposable test strip. This innovation allows anyone with a smartphone to measure their salivary cortisol levels quickly, accurately, and affordably,” said study lead author Joel RL Ehrenkranz, director of the Department of Diabetes and Endocrinology at the medical school. Intermountain Healthcare (USA).

A classic laboratory test is worth between 60 and 100 euros and takes a week. The smartphone test would be worth 5 dollars (3.6 euros) and would only take 10 minutes. And the software is can be used on all platforms including iOS, Android, Windows, and BlackBerry and works with all smartphones.

To market this smartphone cortisol test, researchers must wait for approval from the FDA (Food and Drug Administration), the US health product regulatory agency.

Definition Of Cortisol

Cortisol is a steroid hormone produced from cholesterol and secreted by glands located above the kidneys (the adrenocortical glands ). Its secretion is dependent on another hormone, ACTH produced by the pituitary gland in the brain (ACTH for adrenocorticotrophin).

Cortisol plays several roles in the body, and participates in particular:

  • In the metabolism of carbohydrates, lipids and proteins: it regulates blood sugar by increasing the synthesis of glucose by the liver (neoglucogenesis), but also stimulates the release of lipids and proteins in most tissues
  • To the anti-inflammatory reaction
  • In the regulation of blood pressure
  • To bone growth
  • In regulating the circadian rhythm. See our article Cortisol and the circadian rhythm.
  • To the stress response: cortisol is often nicknamed the stress hormone. Its role is to help the body cope with it, by mobilizing the energy needed to nourish the muscles, the brain and also the heart.

Note that the cortisol level varies according to the time of day and night: it is maximum in the morning and decreases throughout the day to reach its lowest level in the evening.

Why Do A Cortisol Test?

The doctor prescribes an analysis of cortisol levels in the blood to detect damage to the adrenal glands or the pituitary gland. Cortisol and ACTH are often measured at the same time.

The Course Of The Cortisol Analysis

The examination consists of a  blood test, carried out in the morning between 7 am and 9 am. This is when cortisol levels are highest and most stable. The medical staff in charge of the examination takes venous blood, usually at the elbow crease.

Since cortisol levels vary throughout the day, the test may be done multiple times to get a more accurate picture of average cortisol production.

The cortisol level can also be measured in the urine (measurement of urinary free cortisol, especially useful for detecting cortisol hypersecretion). To do this, the urine must be collected in a container provided for this purpose, over a period of 24 hours.

You will be explained the procedure to follow, which generally consists of collecting all the urine of the day (by storing it in a cool place).

Before submitting to the tests (blood or urine), it is recommended to avoid any stressful situation or to do the exercise. The doctor may also ask to stop certain treatments that may interfere with cortisol measurement (estrogens, androgens, etc.).

What Results Can Be Expected From A Cortisol Test?

In the blood, the normal cortisol value assessed between 7 a.m. and 9 a.m. is between 5 and 23 μg/dl (micrograms per deciliter).

In urine, the cortisol level obtained normally is between 10 and 100 μg/24h (micrograms per 24 hours).

High cortisol levels can be a sign of:

  • Cushing’s syndrome (hypertension, obesity, hyperglycemia, etc.)
  • a benign or malignant adrenal gland tumor
  • an acute infection
  • cerebral capsular accident, myocardial infarction
  • or cirrhosis of the liver, or chronic alcoholism

On the contrary, a low cortisol level can be synonymous with:

  • adrenal insufficiency
  • Addison’s disease
  • insufficient functioning of the pituitary gland or hypothalamus
  • or be the consequence of prolonged corticosteroid therapy

Only the doctor can interpret the results and give you a diagnosis (additional examinations are sometimes necessary).


Quick, Easy, Inexpensive Cortisol Testing Should Soon Be Available on All Smartphones


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