Serum/plasma tests
Hormones
Steroid Hormones
Androstenedione
Bioavailable testosterone
Cortisol
DHEA-S
Dihydrotestosterone (DHT) (TOS)
Estradiol
Estradiol-HRT
17-OH progesterone (TOS)
Pregnenolone
Progesterone
Testosterone
Peptide Hormones
Follicle Stimulating Hormone (FSH)
Insulin (TOS)
Luteinizing Hormone (LH)
Secretin (TOS)
Sex Hormone Binding Globulin (SHBG)
Thyroid Stimulating Hormone (TSH)
Vasoactive Intestinal Polypeptide (VIP) (TOS)
Other Hormones
Free Triiodothyronine (FT3)
Free Thyroxine (FT4)
Triiodothyronine (T3)
Thyroxine (T4)
Other

TOS - To be offered shortly


Tests › Serum/plasma tests › Hormones › Steroid Hormones › Cortisol

Cortisol

Significance
Cortisol is the major Adrenal corticosteroid, also referred to as hydrocortisone. Some Important functions include regulation of blood pressure, immune function, cardiovascular function, as well as regulation of metabolism relating to proteins, carbohydrates, and fats. Cortisol is strongly bound to Corticosteroid Binding Globulin in the circulation, with smaller amounts loosely bound to Albumin and some unbound (free form). Cortisol production is under negative feedback from the pituitary/hypothalamus via Adrenocorticotropic hormone and Corticotropin Releasing Factor. It exhibits diurnal variation with highest values early in the morning (6-8 am) and the nadir at 11pm. This diurnal variation is absent in Cushing’s syndrome and also disrupted by number of factors. Cortisol is also called the "stress” hormone because levels increase in response to stressful factors, whether physiological/physical (illness, trauma, surgery etc) or psychological. Measurements of Cortisol levels help diagnose Cushing syndrome and Addison disease, the two major adrenal disorders. However, they are also sometimes used for evaluating possible psychological or stress-related conditions.

Analysis
Determination of Cortisol is performed by enzyme immunoassay.

Patient Preparation
Morning specimen is preferred.

Specimen requirements
Serum specimen - from a plain redtop or a redtop gel (tiger top) tube. Separate serum from cells after centrifugation, if a plain redtop tube is used. Minimum volume required is1 mL. Specimen should be kept refrigerated where possible.

Shipping Instructions
Ship specimen at ambient temperatures. For long distance shipping, ship with ice packs.

Additional information
http://www.labtestsonline.org/understanding/analytes/cortisol/test.html