Blood cortisol measurement is used to distinguish between primary and secondary adrenal insufficiency and the differential diagnosis of Cushing's syndrome.
In response to a stimulus such as stress, the hypothalamus secretes the corticotropin-releasing hormone. This hormone stimulates the secretion of the adrenocorticotropic hormone (ACTH) from the anterior pituitary gland. ACTH in turn stimulates the adrenal cortex to release the glucocorticoid hormone, cortisol. Cortisol has many functions, such as:
- Stimulates glucose formation (gluconeogenesis)
- Stimulates the breakdown of stored energy (fats, proteins, carbohydrates)
- Promotes the response of the sympathetic nervous system to stressors
- It reduces the inflammation and function of the immune system
- Stimulates gastric acid secretion
Determination of cortisol levels in the blood provides valuable information on the function of the adrenal cortex. Cortisol is normally secreted by a daily motif, with its highest being between 6 and 8 in the morning and its lowest around midnight.
Possible Interpretations of Pathological Values
- Increase: Burns, Crohn's disease, Cushing's disease, Cushing's syndrome, eclampsia, exercise, severe liver disease, hyperpituitarism, hypertension, hyperthyroidism, infections, obesity, osteoporosis, acute pancreatitis, pregnancy, severe kidney disease, shock, stress (from heat, cold, trauma, psychological), surgeries. Medications: Corticotropin, estrogen, oral contraceptives, yohimbine, vasopressin, nicotine, synthetic glucocorticoids (prednisone, prednisolone), lithium, ethyl alcohol
- Decrease: Addison's disease, adrenal insufficiency, adrenogenital syndrome, chromophobic adenoma, craniopharyngioma, hypoglycemia, hypophysectomy, hypopituitarism, hypothyroidism, liver disease, pituitary necrosis after childbirth, rheumatoid arthritis, Waterhouse-Friderichsen syndrome. Medications: Dexamethasone (various forms), androgens, barbiturates, levodopa, phenytoin
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.