Insulin

This test is used to find out the Insulin levels in the blood.

What is Insulin?

Insulin is a hormone produced by special cells in the pancreas. Insulin helps in promoting the absorption of glucose (sugar) from the bloodstream into the cells of liver, fat and skeletal muscle. In these cells, glucose is used to produce energy and utilized by the body. These special cells in the pancreas are sensitive to glucose concentrations or blood sugar levels. Insulin production is high when the glucose levels in the blood are high and when glucose levels are low insulin production is low.

Insulin attaches to the target cell receptors and allows the cell to absorb glucose from the blood and the cells utilize the absorbed glucose to produce energy. Insulin thus maintains the blood glucose levels and prevents the hypoglycemia (low in blood glucose or sugar levels) and hyperglycemia (high in blood glucose or sugar levels). If there is more glucose or sugar in the body than needed, insulin helps to store the excess glucose or sugar in the liver. The stored sugar or glucose is released when blood glucose or sugar levels are low or whenever the body needs more glucose such as during physical activity.

Abnormal Insulin secretions:

In any case, insulin secretion is abnormal or stopped, then it may lead to an increase in the blood sugar levels and cause Diabetes mellitus. If special cells in the pancreas are not functional or damaged or destroyed, then the production of insulin is decreased or stopped. As insulin production is stopped due to damaged special cells, target tissue cells cannot absorb the glucose or sugar present in the blood and thus leads to an increase in the blood sugar or glucose levels and leads to Type-1 Diabetes mellitus. If the cells in the body are resistant to the insulin produced or only little amount of insulin is produced which is insufficient for cells, then it leads to the Type-2 Diabetes mellitus.

Why this test is performed?

The doctor may ask to perform this test if the patient is suffering from symptoms like frequent urination, hunger, blurred vision, fatigue, increased thirst or dry mouth, unexplained weight loss or weight gain, poor wound healing, foot pain and numbness, frequent infections, itching around penis or vagina, sweating, fast heart rate, sleepiness, headache, nausea and vomiting which are common symptoms of Diabetes mellitus.

In some cases, this test is performed to find out the effectiveness of the treatment. If a patient is on the treatment of diabetic medications like insulin and other antidiabetic drugs, then the doctor may ask to perform this test to evaluate and to check the insulin blood levels in the body. This helps the doctor to rule out the patient disease condition. Along with this test, some other insulin and glucose tests may be recommended by a physician to confirm the diagnosis.

This test is also done to know whether an individual is having pancreatitis (inflammation in the pancreas), Cushing syndrome (pink and purple stretch marks along with round face and large tummy), acromegaly (enlargement of the face, hand, and feet), insulinomas (excess production of insulin due to tumor in the pancreas). Generally, when a patient is diagnosed with the Diabetes mellitus visits hospital for a general check-up, the doctor may ask to undergo Insulin fasting test which gives a better status of insulin secretion by the pancreas and its condition.

Precautions:

Drugs like corticosteroids, levodopa, oral contraceptives may change the levels of Insulin in the blood. So, inform your doctor prior to the test if you are on these medications.

Frequency:

For individuals above 45 years of age, this test is recommended every 3 years. The frequency of this test depends on various factors like body weight, history of heart disease, high blood pressure, gestational diabetes, imbalance of female sex hormones, a family member with diabetes, physically inactive, polycystic ovary disease, etc. Children above 10 years of age with any of two above-mentioned risk factors should be recommended to this test at least once in every 3 years even with no symptoms.

If the test results are in normal range, then the insulin production by the pancreas is normal and no need for medical intervention.

If test results are greater than the normal range, then it may be due to overweight, insulinoma, Type-2 Diabetes Mellitus, infantile hypoglycemia, hyperinsulinism (increase in the insulin levels than the normal range), Cushing’s syndrome (pink and purple stretch marks along with round face and large tummy), acromegaly (enlargement of the face, hand, and feet), hyperthyroidism (excess production of hormones from thyroid gland), insulin resistance.

If test results are lower than the normal range, then it may be due to hypopituitarism (decreased in hormone production by the pituitary gland), Type-1 Diabetes Mellitus, cystic fibrosis, pancreatitis (inflammation in the pancreas), pancreatic cancer (cancer in the pancreas), untreated Type-1 Diabetes mellitus.