01
Which samples are used?
MedlinePlus describes three main approaches. Blood is drawn in a healthcare setting; saliva may be collected with a kit following precise instructions; urine testing may require a 24-hour collection.
- Blood: the time of the draw matters.
- Saliva: multiple samples at different times may be needed.
- Urine: completing the collection requested by your clinician is essential.
02
How should you prepare for a test?
Follow the instructions for your specific test. Stress, exercise and some medicines can affect cortisol. Tell your health professional about all medicines you use, including creams and products containing corticosteroids.
Some saliva collections have instructions about food, drinks and oral hygiene before sampling. Do not substitute a generic online procedure for laboratory instructions. Do not stop medicines on your own.
03
What does a high or low result mean?
A result outside the laboratory range needs interpretation in clinical context. Cortisol changes during the day and an isolated test cannot establish the cause of an abnormality. Additional tests may be needed.
Tests are used, among other purposes, to investigate conditions such as Cushing’s syndrome or adrenal insufficiency. Do not turn a result into a diagnosis of stress or an automatic assessment of a wellness treatment’s effectiveness.
Sources consulted
References used for this article.
Frequently asked questions
Can I compare tests taken at different times?
Not without accounting for timing and protocol. Cortisol naturally changes during the day: ask your clinician how to interpret the comparison.
Does a saliva test measure how stressed I am?
It measures cortisol in the collected sample. By itself it does not fully measure your experience of stress or provide a diagnosis.