This test is administered at home using a test kit which can be picked up by the patient at a local PSC (See: Resource Collection Note). Cortisol is thought to be most accurate when tested through saliva while most other hormones are more accurate with blood testing (serum). This test for adrenal insufficiency includes 4 measurement of the salivary Cortisol level. Cortisol, also known as the "stress hormone" can be either too high or too low which may be a sign of adrenal distress. Cortisol is the main adrenal glucocorticoid and plays a central role in glucose metabolism and in the body's response to stress. Adrenal cortisol production is regulated by adrenocorticotropic hormone (ACTH), which is synthesized by the pituitary gland in response to hypothalamic corticotropin-releasing hormone (CRH). Serum cortisol in turn inhibits the production of both CRH and ACTH (negative feed-back loop), and this system self-regulates to control the proper level of cortisol production. The coordinated stimulatory and inhibitory connections between CRH, ACTH, and cortisol are referred to as the hypothalamic-pituitary-adrenal (HPA) axis.