The insulin tolerance test examines pituitary and adrenal function by injecting insulin into a patient's vein to lower their blood sugar level. It involves fasting overnight, having normal ECG and weight recorded, then a fixed dose of insulin is injected and the patient is monitored for 20-40 minutes. A normal cortisol response is above 550 nmol/L while levels below 550 nmol/L indicate impaired response requiring treatment. Growth hormone should rise above 20 mU/L. Side effects include sweating, palpitations and potential loss of consciousness so those over 60, with heart issues, or hormone disorders cannot have the test.

1. Insulin Tolerance Test
Amit Kumar Singh
Assistant Professor
Department of Medical Lab Technology
Chandigarh University, Punjab

2. Insulin Tolerance Test
Insulin tolerance test is a medical diagnosis
process during which insulin is injected into a
patient vein to examine,
• Pituitary function
• Adrenal function for other purpose.
An ITT is usually ordered and interpreted by the
endocrinologist

3. Purpose
Insulin tolerance test is the diagnostic Test for
the assessment of the pituitary and adrenal
function
Procedure
Before the test the patients should fast
overnight where as the ECG should be normal
and patient weight. Then a fix doses of insulin
is injected into the vain so that insulin can be
easily absorbed into the blood. It is necessary
to wait for 20 to 40 minutes to see the result.

4. Normal range
• An average cortisol level must be greater than 550 nmol/L
where when the cortisol level is less than 550 but greater
than 400 nmol/L. It is called impaired cortisol response,
which required steroid for the treatment of ailments or
different type of stress. The average level for the response
of the growth hormone occur when the level rises to 20
mU/L. Cushing syndrom (it occurs when the level of cortisol
rises but remains less than 170nmol/L) is an endocrine
disorder, which is caused by a high level of cortisol ion in
the blood that causes tumor in the pituitary gland which
produces a large amount of adrenocorticotropic hormone
(ACTH). However when the level of cortisol is less than the
range of 170 nmol/L it is called pseudo sudo cushing
syndrome.

5. Result
• The side effect of this test include sweating, palpitations,
loss of consciousness and rare convulsions. However sever
hypoglycemia may result in the patient going into the
comma.
• The preparation for the insulin tolerance test is that before
the test the patients should fast overnight with the ECG
being normal and patient weight known.
• Then a fixed doses of insulin is given to the patient which is
injected into the vain so that the insulin can be easily
absorb into the bloodstream and stay there for 20-40
minutes.
• A fall in the blood sugar level gives rise to symptoms such
as drowsiness, thirst, hunger, tiredness, headache and rapid
heart beat. However, when the hormone suddenly
synthesizes insulin then the patients feels better.

6. Precaution
• After the test the person should not drive
immediately and should take rest for 2hr.
Insulin tolerance test cannot be recommended
for the following:
• Above the age of 60 and children
• Heart patients (ischaemic heart disease
{decreses the blood supply to the heart})
• Patients to the hyporadrenalism
• Patients of panhypopituitarism