Cortisol in Human Serum with Roche e801

Detection of Cortisol in Human Serum with Roche e801

Test Name: Immunoassay for the in vitro quantitative determination of cortisol in human serum and plasma.
Method Name: The Elecsys Cortisol II assay makes use of a competition test principle using a monoclonal antibody which is specifically directed against cortisol. Endogenous cortisol which has been liberated from binding proteins with danazol competes with exogenous cortisol derivative in the test which has been labeled with ruthenium complex for the binding sites on the biotinylated antibody.
Results: Technical Range: 0.109-63.4 µg/dL
Reportable Range: 0.248-63.4 µg/dL
Reference Ranges: A.M.: 7-25 µg/dL
P.M.: 2-14 µg/dL
Clinical Significance: The determination of cortisol is used for the recognition and treatment of functional disorders of the adrenal gland.

Cortisol (hydrocortisone) is quantitatively the major glucocorticoid product of the adrenal cortex. The main reason to measure cortisol is to diagnose human diseases which are caused by the overproduction of cortisol in Cushing’s syndrome (CS), deficiency of adrenal steroid excretion in Addison’s disease, and for therapy monitoring (e.g. dexamethasone suppression test in Cushing’s syndrome and hormone replacement therapy in Addison’s disease).

Cortisol plays an important role in the regulation of many essential physiological processes, including energy metabolism, maintenance of electrolyte balance and blood pressure, immunomodulation and stress responses, cell proliferation as well as cognitive functions. The major fraction of cortisol circulates bound to plasma proteins as corticosteroid binding globulin and albumin. The biologically active free fraction comprises only 2-5 % of the total hormone concentration.

Elevated serum levels can be found in stress responses, psychiatric diseases, obesity, diabetes, alcoholism and pregnancy, which may cause diagnostic problems in patients with Cushing’s syndrome.

Low levels of cortisol are seen in patients with rare adrenal enzyme defects and after long-lasting stress.

The secretion of cortisol is mainly controlled by the hypothalamic-pituitary-adrenal axis (HPA). When cortisol levels in the blood are low, a group of cells in a region of the brain called the hypothalamus release corticotropin-releasing hormone (CRH) which causes the pituitary gland to secrete another hormone, adrenocorticotropic hormone (ACTH), into the bloodstream. High levels of ACTH are detected in the adrenal glands and stimulate the formation and secretion of cortisol, causing blood levels of cortisol to rise. As the cortisol levels rise, they start to block the release of CRH from the hypothalamus and ACTH from the pituitary.

Normally, the highest cortisol secretion happens in the second half of the night with peak cortisol production occurring in the early morning. Following this, cortisol levels decline throughout the day with lowest levels during the first half of the night. Therefore, the circadian variations of cortisol secretion and the influence of stress have to be considered for the sampling conditions in serum and plasma.

Submission Criteria: For specimen collection and preparation, only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Plasma: Li-heparin and K2-EDTA plasma
Do not use fluoride plasma

The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, therefore not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases.  When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
Storage and Stability:    12 months at -20°C
4 days at 2-8°C

Rejection Criteria: Rejection criteria include but are not limited to:
1. Specimens containing fibrin or clots.
2. Excessive platelet clumping
3. Leaking specimens
4. Substandard mixing or collection
5. Expired or improperly stored collection tubes.
6. Improperly filled tubes based on collection tube manufacturer’s guidelines.
7. Contaminated specimens (IV fluid, foreign particles, etc.)
8. Specimens not analyzed within the appropriate time frame.
9. Samples not shipped at appropriate temperature.
10. Samples without 2 proper identifiers or samples having identifiers that do not match the electronic or paper lab requisition.
Authorization: Diagnostic testing can only be performed with approval from an authorized provider/agency.
Turn Around Time: 1 day.