Cortisol level, Hydrocortisone (AM and PM)
- It is done on serum (3-5 ml clotted blood).
- Also, it can use plasma.
- Collect the blood at 8 AM.
- Then collect blood at 4 PM.
- 4 PM value is one third to two-thirds of the 8 AM value.
- The sample can be stored at 4 °C for 2 days.
- For longer period freeze the sample.
- Urine sample. This is a 24 hours sample. Add Acetic acid (30%) 20 ml to the container.
- Or preserve with 1 gram boric acid.
Purpose of the test (Indications)
- This will measure the serum cortisol level.
- Cortisol level is estimated to rule out hypo or hyperfunction of the adrenal gland.
- There is increased value during pregnancy.
- Emotional and physical stress can increase value.
- Drugs like amphetamine, estrogen, cortisone, oral contraceptives, and spironolactone can increase value.
- Drugs like androgens, betamethasone, exogenous steroids, lithium, danazol, Dilantin, and methyldopa can decrease the value.
- This is major adrenal gland glucocorticoid synthesized in the zona fasciculate of the adrenal cortex and this will control the metabolism of:
- Glucose (carbohydrate).
- Lipids (fats).
- The adrenal glands produce various steroids.
- This hormone is involved in the metabolism of the body.
- Cortisone and its oxidation products cortisone are inactivated in the liver by two separate reduction process (hydrogenation) into tetrahydro-derivates.
- This will conjugate with glucuronic acid in the liver and then excreted in the urine.
- Cortisol is a steroid.
- Because of its tight bonding with Cortisol-binding-globulin, cortisol is metabolized slowly.
- The kidney, liver, and thyroid diseases affect the secretion and metabolism of the cortisol (adrenal gland steroids).
- Other factors that affect the cortisol level are our age, stress, nutrition, estrogen therapy, and drugs.
- Glucocorticoid hormone is secreted 10 to 30 mg/ 24 hours that influence the Carbohydrate metabolism.
- Adrenal Cortisol roughly 25 mg produced in 24 hours, while plasma concentration is 5 to 25 µg/dL.
- Cortisol takes part in the metabolism of carbohydrates, protein, and fats.
- Cortisol breakdown the proteins.
- There is an amino acid formation.
- Amino acids converted into glucose.
- Cortisol is an insulin antagonist.
- Cortisol breakdown the proteins.
- Cortisol is glucocorticoid secreted by the adrenal cortex in response to ACTH stimulation.
- Cortisol is formed by the cholesterol in the adrenal zona fasciculata and reticularis of the adrenal cortex.
- After entering into the blood circulation, it will bind with corticosteroid-binding globulin.
- Cortisol will be metabolized and conjugate in the liver.
- >95% cortisol metabolites conjugated with glucuronic acid and excreted in urine as such.
- <2% unmetabolized cortisol is excreted in the urine.
- Cortisol transported as:
- Bound form.
- 85% binds the corticosteroid-binding α-globulin (transcortin).
- 10% bound to albumin.
- Approximately 5% is free.
- ACTH is under the control of the hypothalamus, Corticotropin-releasing hormone (CRH).
- In case of increased ACTH, after a few minutes cortisol is excreted.
- Decreased ACTH level leads to the atrophy of zona fasciculata (and zone reticularis).
- Exogenous glucocorticoids lead to suppression of ACTH and adrenocortical atrophy.
- Corticotropin-releasing hormone ( CRH ) made in the hypothalamus, stimulates the anterior pituitary gland to produce ACTH which stimulates the adrenal cortex to produce cortisol.
- Cortisol in blood exists in the following form:
- Cortisol free.
- Cortisol in total.
- <2% cortisol is excreted unchanged in the urine.
- Cortisol controls the glucose level in the blood.
- Cortisol increases glucose level by increasing gluconeogenesis in the liver (from glucose store).
- It has an inhibitory effect on insulin so stop the transport of the glucose into the cells.
- There is diurnal variation in the secretion of cortisol in the morning and as well evening or midnight cortisol level. So a random sample is not useful.
- Cortisol level is:
- Highest between 6 to 8 AM.
- Lowest between 4 to 6 pm. (Gradually false during the day, lower between 4 to 6 pm.)
- The lowest level is at midnight.
- Cushing’s syndrome has the upper normal level in the morning.
- There is no decline throughout the day.
- Addison disease has the lowest level.
- Cortisol takes a role in the immune system.
- It is influenced by heat, cold, infection, trauma, exercise, debilitating diseases, and obesity.
- Cushing’s syndrome does not show diurnal change.
- The variation is lost under the stress.
- Mostly >1%of the total cortisol is synthesized daily is excreted as such in the urine.
- 30 to 50% appears in the form of glucuronide conjugates as tetrahydro-derivates of cortisol and cortisone.
- All these compounds contain dihydroxyacetone group in the side chain, known as 17-hydroxycorticosteroid (17-OHCS).
- There is a higher concentration of these compounds in the urine.
- Chemical estimation of the urinary 17-OHCS or of 17-Ketogenic steroids does not give a true estimation of the plasma cortisol concentration or output because they may form from other steroids similar in structure.
Normal Total Cortisone
- Serum AM (8 am) = 5 to 23 µg/dL
- Serum PM (4 pm) = 3 to 13 µg/dL
- Urine (free cortisol) = 20 to 90 µg /24 hours
- Children = 1 to 16 years.
- 8 AM = 15 to 25 µg/dL
- 4 PM = 5 to 10 µg/dL
- Newborn = 1 to 24 µg/dL
- Maternal at birth = 51.2 to 57.4 µg/dL
- The blood sample was usually taken at 8 AM and 4 PM where 4 Pm level is one third to two-third lower than 8 AM level.
- Urine 24 hours
- Adult / old people = <100 µg/dL/24 hours (<276 nmol/day).
- Adolescent = 5 to 55 µg/dL/24 hours
- Child = 2 to 27 µg/dL/24 hours
Total Cortisol (free and bound by RIA)
|Cord blood||5 to 17||138 to 469|
|Infant 1 to 7 days||2 to 11||53 to 304|
|Child 1 to 16 years||3 to 21||83 to 580|
|0080 AM||5 to 23||138 to 635|
|1600 PM||3 to 16||83 to 441|
|2000 PM||<50% of 0800 AM value||<50% of 0800 AM value|
|Maternal at birth||54.3 ± 3.1|
|Cortisol Free 24 hours of urine|
|1 to 10 year||2 to 27/day||6 to 74|
|11 to 20 year||5 to 55||14 to 152|
|Adult||20 to 90||52 to 248|
|Serum (free cortisol)|
|0800 AM||0.6 to 1.6||1.7 to 4.4|
|1600 PM||0.2 to 0.9||0.6 to 2.5|
- For conversion of µg/dL into SI unit x 27.6 = nmol/L
- 0800 AM =5 to 23 µg/dL (138 to 635 nmol/L).
- 4.00 PM = 3 to 16 µg/dL (83 to 441 nmol/L).
- Midnight = <50% of 0800 Am level.
- Newborn = 2 to 11 µg/dL (55 to 304 nmol/L).
- Maternal at birth = 52.1 to 57.4 µg/dL (1413 to 1584 nmol/L).
- After the first week of life cortisol level is like an adult level.
The increased level is seen in:
- Cushing syndrome,( Pituitary disease)
- adrenal adenoma and carcinoma.
- Pregnancy leads to a raised level.
- Physical and emotional stress can increase levels.
- Ectopic ACTH-producing tumors.
- Major depression.
- Severe anxiety.
- Obesity. All the steroids hormone are increased in obese and this may be due to deposition or synthesis in the fat.
- The extremely high level is seen in Ectopic ACTH syndrome.
The decreased level is seen in:
- Addison disease.
- congenital adrenal hyperplasia ( adrenogenital syndrome )
- Cushing,s syndrome is the result of an increase in serum cortisol production.
- Clinical presentation:
- There is truncal obesity.
- Neuropsychiatric symptoms.
- There is hypertension.
- There is an intolerance of carbohydrates.
- There is hyperglycemia and decreased glucose tolerance.
- There are polyuria and polyphagia.
- There are hirsutism and acne.
- There are proximal myopathy and weakness.
- The patients are prone to easy bruises.
- There are sexual dysfunction and menstrual problems.
- Lab. diagnosis:
- There is hypokalemic metabolic alkalosis.
- There is an increase in urinary free cortisol.
- Diurnal variation may be absent in the Cushing’s syndrome.
- There is a lake of normal suppression by dexamethasone.
- A high level of cortisol indicates Cushing’s syndrome.
- A low level of cortisol indicates Addison’s disease.
Table for differentiation of Adrenal diseases
|Disease||ACTH value||Cortisol value|
|Cushing’ syndrome causes|
|ACTH- producing Pituitary tumor||Raised||Raised|
|Ectopic ACTH (Lung cancer)||Raised||Raised|
|Addison disease causes|
|Adrenal gland failure ( Infarction, Haemorrhage||Raised||Low|
|Congenital adrenal hyperplasia||Raised||Low|
Urinary cortisol per/day in various diseases:
|Disease||µg free cortisol/day|
|Ectopic ACTH syndrome||>120|