Insulin Test

Insulin test is a kind of laboratory test that measures the insulin hormone level in the blood. Insulin is a hormone that is produced by pancreas and excreted when the blood glucose level increases. Insulin hormone is related with sugar transport to cells and intracellular energy production. Insulin helps to reduce the blood glucose level and also has a role in blood fats metabolism. Diabetes occurs if  insulin production is not enough or there can be enough insulin but person may have insulin resistance . In diabetes, blood sugar level increases but sugar can’t get into the cells. High blood glucose level cause problems in kidneys, heart, vessel, nerves and eyes. On the other hand so much insulin will be  produced if there is insulinoma tumor. This tumor type causes so low blood glucose level and this may be fatal for patient.


Insulin production in the body

Insulin is produced and stored in pancreas beta cells. Blood glucose level regulates insulin production. If the blood sugar level increases, insulin is  excreted from the beta cells and mixes to the blood stream

How the insulin test is done ?

A blood sample is needed for insuline test. A needle will be inserted to your arm vein and a tube of blood will be collected. You don’t need to worry about blood collection procedure. All process takes 1-2 minutes and you may feel a little pain for a few seconds only.

Preparation for insulin test

You may need to fast before the test. Your doctor will inform you about fasting and other subjects. Please inform your doctor about the medicines you use.

Why the insulin test is done? Purpose of insulin test

  • To determine when to start treatment in diabetes type-2
  • Determination of insulin amount that is produced in pancreas
  • Determination of insulin resistance
  • Determination the cause of blood sugar level
  • Diagnosing insulinoma tumor
  • Evaluating the success of islet cell transplantation with using other tests like blood glucose level or C-peptide test.

Insulin test normal values

These values may change according to the laboratory, test method and the analyser

Blood insulin range: 1.9-23 mcU/mL

High insulin results causes

  • Cushing’s syndrome
  • Insulin resistance
  • Insulinoma
  • Obesity
  • Fructose intolerance
  • Galactose intolerance
  • Acromegaly
  • Corticosteroids usage
  • Levodopa usage
  • Birth control pills usage

Low insulin results causes

  • Diabetes
  • Pancreas diseases
  • Chronic pancreatitis
  • Pancreas cancer
  • Insulin C-peptide ratio

Insulin and C-peptide both are excreted at the same ratio, but half of insulin is removed by liver so insulin will be found for a shorter time in blood circulation. C-peptide is removed by kidneys. So C-peptide’s half-life will be 5 times of insulin because it is 30 minutes and insulin’s half-life is about 5-8 minutes. Insulin and C-peptide are  both released same amount to the blood circulation but they will be found in blood circulation 1/5 to 1/15. This ratio helps to find the low blood glucose is caused by insulinoma or insulin usage.


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