Understanding a patient’s cortisol levels is important to diagnose and treat several co-morbid conditions, including Cushing’s syndrome and Addison’s disease. A patient’s cortisol levels can also provide insight into his or her overall wellness, including sleep patterns and stress levels. (American Association of Clinical Endocrinologists, 2018).

Although blood and saliva contain different amounts of cortisol, both provide accurate measurements. Testing saliva can help monitor cortisol levels over time. Saliva tests are less invasive and more cost-effective than blood tests. Furthermore, patients requiring frequent testing can avoid additional trips to the doctor for blood draws since salivary testing can be performed at home. Therefore, saliva testing is a preferred method of monitoring cortisol levels.

Keevil, B. G., MacDonald, P., Macdowall, W., Lee, D. M., Wu, F. C., & NATSAL Team (2014). Salivary testosterone measurement by liquid chromatography tandem mass spectrometry in adult males and females. Annals of clinical biochemistry, 51(Pt 3), 368–378. https://doi.org/10.1177/0004563213506412

A blood test has historically been the most common way to detect cortisol. Blood is drawn from an arm vein and sent to a laboratory for analysis. (U.S. National Library of Medicine).

Although blood and saliva contain different amounts of cortisol, both provide accurate measurements. Testing saliva can help monitor cortisol levels over time. Saliva tests are less invasive and more cost-effective than blood tests. Furthermore, patients requiring frequent testing can avoid additional trips to the doctor for blood draws since salivary testing can be performed at home. Therefore, saliva testing is a preferred method of monitoring cortisol levels. (Keevil, 2014)

Keevil, B. G., MacDonald, P., Macdowall, W., Lee, D. M., Wu, F. C., & NATSAL Team (2014). Salivary testosterone measurement by liquid chromatography tandem mass spectrometry in adult males and females. Annals of clinical biochemistry, 51(Pt 3), 368–378. https://doi.org/10.1177/0004563213506412

Cortisol testing may be recommended at different intervals depending on physicians’ recommendations and treatment plans. Depending on the patient, testing might be needed every few months or once a year. For instance, a patient with Addison’s disease might need more frequent monitoring than a patient with Cushing’s disease. (American Association of Clinical Endocrinologists, 2018)

Cortisol is a hormone naturally produced by the adrenal glands. (MedlinePlus Medical Encyclopedia. It is essential because it helps the body respond to stress, regulates blood sugar levels, and supports immunity. Furthermore, cortisol influences weight management, weight gain, and high blood pressure.

1. Adrenal glands: MedlinePlus Medical Encyclopedia. (n.d.). https://medlineplus.gov/ency/article/002219.html
2. Arafah BM, Nishiyama FJ, Tlaygeh H, Hejal R (2007) Measurement of salivary cortisol concentration in the assessment of adrenal function in critically ill subjects: a surrogate marker of the circulating free cortisol. Clinical Endocrinoly Metabolism 92: 2965-2971.

Fatigue, weakness, nausea, and low blood pressure are common symptoms of low cortisol levels. A woman may also experience irregular periods or missed periods, while a man may experience erectile dysfunction.

Inder, W. J., Dimeski, G., & Russell, A. (2012). Measurement of salivary cortisol in 2012 – laboratory techniques and clinical indications. Clinical endocrinology, 77(5), 645–651. https://doi.org/10.1111/j.1365-2265.2012.04508.x

Low cortisol levels can increase the risk of wellness issues, including fatigue, weakness, sleep regulation, and dehydration (Lieberman et al., 2005; Liu & Reddy, 2022). Low cortisol levels can sometimes lead to severe co-morbidities, such as Addison’s disease. (National Institute of Diabetes and Digestive and Kidney Diseases, 2017).

Lieberman, H. R., Bathalon, G. P., Falco, C. M., Kramer, F. M., Morgan, C. A., 3rd, & Niro, P. (2005). Severe decrements in cognition function and mood induced by sleep loss, heat, dehydration, and undernutrition during simulated combat. Biological psychiatry, 57(4), 422–429. https://doi.org/10.1016/j.biopsych.2004.11.014

Liu, P. Y., & Reddy, R. T. (2022). Sleep, testosterone and cortisol balance, and ageing men. Reviews in endocrine & metabolic disorders, 23(6), 1323–1339. https://doi.org/10.1007/s11154-022-09755-4

National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Adrenal insufficiency and Addison’s disease. https://www.niddk.nih.gov/health-information/endocrine-diseases/adrenal-insufficiency-addisons-disease

The threshold for low cortisol levels can vary depending on the individual and the laboratory conducting the test. Validated testing chemistries and lab equipment are specific and unique to each laboratory developed test (LDT) and testing brand, because of this reported lab results on the same patient can vary from one testing brand to the next. However, according to research by Aardal & Holm, 1995, in general, cortisol levels between 0.094–1.551 µg/dL are considered the normal range for morning salivary measurements.

Aardal, E., & Holm, A. C. (1995). Cortisol in saliva–reference ranges and relation to cortisol in serum. European journal of clinical chemistry and clinical biochemistry : journal of the Forum of European Clinical Chemistry Societies, 33(12), 927–932.
https://doi.org/10.1515/cclm.1995.33.12.927