Cortisol Blood Test: Purpose, Process and Result Interpretation

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A cortisol blood test is conducted to determine the cortisol hormone level in the blood. Cortisol assists the body in metabolism and stress management. The levels of cortisol in the blood may vary because of several factors like stress, infection, injury and strenuous activities. The levels of cortisol usually vary during the span of the day. In the morning, it is generally increased, and at night and during sleep, its level is often low. Its level, however, may follow the person’s sleeping habits. Those who sleep in the daytime and are awake at night, may have reversed cortisol level patterns also.

This test can help determine if a patient has problems concerning their pituitary gland or adrenal glands that might be causing abnormal hormone production. This amount of production affects body systems like the immune system, the bones, the nervous system, the circulatory system, the person’s response to stressful situations, and in the metabolism of protein, fats and carbohydrates.

Cortisol Blood Test Procedure

The patient is often asked to stop the intake of drugs that may affect cotrisol measurements. These drugs may include estrogen, androgens, phenytoin and synthetic glucocorticoids like prednisolone and prednisone. The test for cortisol may be taken twice, morning and afternoon.

The test involves drawing of blood through an arm vein. The vein area will be cleaned using antiseptics, and then an elastic band is wrapped on the upper arm, putting pressure and causing the vein to swell with blood. A needle is then gently inserted in the vein and blood is collected using an airtight test tube that is attached to the needle. After the right amount of blood is collected, the elastic band and needle are removed. The punctured area is immediately covered to prevent any bleeding.

Result of the Test

Abnormal levels of cortisol in the body may indicate several conditions. If the level of cortisol is higher than normal, this frequently suggests Cushing syndrome, some types of cancer, adrenal tumor, or an ectopic ACTH-producing tumor. Cushing syndrome may be caused by depression, obesity, hyperthyroidism, liver disease or kidney disease. If the level is lower than normal, this often suggests Addison’s disease and hypopituitarism.

Symptoms of Cushing syndrome include high blood pressure, high blood sugar levels, round reddish face, fatigue, presence of pads of fat in the chest and the upper back, diabetes, emotional changes and easy bruising. Addison’s disease is a disorder that causes fatigue, muscle pains and weakness, joint pains, weight loss, sweating, anxiety, dizziness, and changes in mood and personality. Some patients may also experience sudden drops in blood pressure when standing up from a seated position.

Several factors can affect the result of the test. These include stress, undergoing radioactive scan a week before the test, hypoglycemia, medication, pregnancy, and eating or exercising before having the test conducted.


WebMD: Cortisol in Blood

MedlinePlus: Cortisol Level