Glucose Fasting And Post Prandial Blood

This test measures the Insulin levels in the blood after 8 hours of fasting or whole night fasting and/or after 2 hours of post-meals. Insulin is a hormone produced by the beta cells of the pancreas. Insulin helps in absorption of glucose (sugar) from the bloodstream into the cells of the body. In these cells, glucose is used for the production of energy, which is utilized by the body. In healthy individuals, insulin production is high when the glucose levels in the blood are high and insulin production is low when the glucose levels in the blood are low.

Insulin maintains blood glucose levels and prevents hypoglycemia (low blood sugar levels) as well as hyperglycemia (high blood sugar levels). Insulin converts the excess sugar in the blood into glycogen for storage.

If insulin secretion is abnormal or if the body is unable to produce insulin, it may lead to an increase in the blood sugar levels; this may cause Diabetes mellitus. If the body is unable to produce insulin, it may lead to type 1 diabetes mellitus. If the body produces an insufficient amount of insulin or if the body cells are resistant to insulin, this may lead to type 2 diabetes mellitus.

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, and nausea and vomiting, etc. 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’s 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 performed to understand 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), or insulinomas (excess production of insulin due to tumor in the pancreas).

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

Increased levels of insulin may be due to obesity, 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), or insulin resistance, etc.

Decreased levels of insulin may indicate hypopituitarism (decrease in hormone production by the pituitary gland), Type-1 diabetes mellitus, cystic fibrosis, pancreatitis (inflammation in the pancreas), pancreatic cancer, etc.

Fasting Insulin test is done after you fasted (without eating anything) for a whole night or for 8 to 12 hours. Usually, the blood is drawn in the morning after an overnight fasting.

The Postprandial test is done after 2 hours of meal consumption. Usually, the blood is drawn in the morning after 2 hours of breakfast or in the afternoon after 2 hours of meals.