Cortisol is a steroid hormone. It is produced by the adrenal gland in the human body. A variation in the level of cortisol production from normal is considered to be a sign of either Cushing's syndrome or of Addison's disease.
A cortisol test uses blood or urine as the sample fluids for testing. In the case of a cortisol test using the blood, it is drawn from a vein in the upper forearm in the same way as blood is drawn for any blood test. Blood is collected in a vial and sent to a laboratory for analysis. Blood may be collected a few times in a day to analyze whether the level of cortisol is falling, as it normally does through the day, or is fluctuating without any defined pattern. In the case of a urine test, the urine is collected throughout the day to analyze the same variation in the level of cortisol through the day by collecting samples in the morning, during the day and at night prior to sleep.
Cortisol is released after the adrenal gland has been stimulated by the brain. This stimulation occurs as a result of the brain releasing the Adrenocorticotropic hormone. An abnormal level of the cortisol hormone in the blood is related either to a malfunctioning adrenal gland or an abnormal release of the ACTH hormone from the brain. This can be diagnosed by stimulating the adrenal gland using a synthetic ACTH substitute that is injected into the individual's bloodstream when testing is being performed.
Addison's disease causes symptoms that include tiredness, muscle weakness, dizziness, sweating and even difficulty in holding one's own weight up. Patients suffering from Addison's disease are also likely to suffer from darkened skin that occurs all across the body and not only in areas that are exposed to sunlight. Patients of the condition also suffer from a condition where their blood pressure falls when they are standing and rises when they are sitting down. It is an incurable condition but it is a condition that can be easily managed by adding the required hormones into the body through artificial sources. It is, however, a dangerous condition that can be termed as a medical emergency if it is allowed to persist for a period of time. The condition could worsen to a point where a patient requires urgent medical attention, especially due to the excessively low blood pressure condition.