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Insulin Fasting

Also known as Fasting insulin, Insulin serum, Insulin F

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You need to provide

Blood

This test is for

Male, Female

Test Preparation

Overnight fasting (8-12 hrs) is required. Do not eat or drink anything except water before the test.

Understanding Insulin Fasting

What is Insulin Fasting?

An Insulin Fasting test measures the insulin level in the blood after an overnight fast (8-12 hours). Insulin is a hormone the pancreas produces that regulates blood sugar (glucose) levels. Fasting insulin levels provide insights into insulin sensitivity (how well the body responds to insulin) and help assess glucose metabolism and the risk of developing insulin resistance-related conditions.

Insulin helps the body cells to uptake glucose (blood sugar) from the blood to produce energy. Insulin resistance occurs when cells do not respond effectively to insulin, leading to elevated blood sugar levels. An Insulin Fasting test provides information about insulin resistance and abnormal glucose metabolism, which is commonly associated with conditions like diabetes, obesity, metabolic syndrome (a collection of conditions including abdominal obesity, high blood pressure, high blood sugar, and abnormal lipid levels), and polycystic ovary syndrome (PCOS).

An Insulin Fasting test is usually done with other glucose-related tests, such as fasting blood glucose or oral glucose tolerance tests. Your doctor may advise this test following a low blood glucose test result and/or if you have low blood glucose (hypoglycemia) symptoms, such as profuse sweating, nervousness or anxiety, irritability, confusion, dizziness, hunger, fast heartbeat, etc. This test may also help detect the presence of an insulin-producing tumor in the islet cells of the pancreas (insulinoma).

An Insulin Fasting test is generally safe and well-tolerated. However, as with any blood test, minimal discomfort or bruising may occur at the site where the blood sample is drawn. Overnight fasting (8-12 hours) is recommended before undergoing an Insulin Fasting test. Do not eat or drink anything other than water during the fasting period. It is also essential to inform your doctor about any medicines you take, as some may affect your blood glucose levels and need to be adjusted or temporarily discontinued before the test.

Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. The results will help them determine your medical condition, make recommendations for lifestyle modifications such as diet and exercise, decide whether or not medication will be required to manage your condition and formulate your overall treatment plan.

What is Insulin Fasting used for?

An Insulin Fasting test can be done:

To assess insulin levels and the body's ability to regulate blood sugar levels
To assess diabetes risk and guide preventive measures.
To identify insulin sensitivity and resistance that is associated with conditions like diabetes, obesity, metabolic syndrome, and polycystic ovary syndrome (PCOS).
To guide management strategies in individuals with metabolic syndrome and PCOS.
To determine the presence of insulin-producing tumors (insulinomas) in the beta cells of the pancreas.

What does Insulin Fasting measure?

An Insulin Fasting test evaluates the body's ability to regulate blood sugar levels by measuring the amount of insulin in the blood after an overnight fast. Glucose is a source of energy for the body to perform daily activities. Your body gets glucose from carbohydrates that are consumed in the diet. These carbohydrates are digested and converted into simple sugar (glucose). The cells then absorb the required amount of glucose to produce energy, and the remaining amount is stored in other forms, like fats. Insulin hormone helps the cells to uptake glucose from the blood for utilization and storage. Thus, it is necessary to maintain insulin levels in your body.

Interpreting Insulin Fasting results

Interpretations

Normal range (Approx.): 2.0 - 25.0 uU/ml

A fasting Insulin test is usually ordered with a Fasting glucose test, and the results are interpreted as follows:

Fasting insulin level	Fasting glucose level	Disorder
Normal	Normal	None
High	Normal or slightly high	Insulin Resistance
Low	High	Insufficient insulin production, e.g., diabetes
Normal or high	Low	Hypoglycemia due to over-secretion of insulin

Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Insulin Fasting

Frequently Asked Questions about Insulin Fasting

Q. What does an Insulin Fasting test measure?

An Insulin Fasting test measures the total amount of insulin in the blood after a period of overnight fasting (8-12 hours).

Q. Which diseases are diagnosed with an Insulin Fasting test?

An Insulin Fasting test helps identify conditions like hypoglycemia (low blood glucose), hyperglycemia (high blood glucose), and insulinoma (the presence of an insulin-producing tumor in the islet cells of the pancreas).

Q. Why is fasting required for an Insulin Fasting test?

The insulin levels in your body spike when you eat or drink anything, which can cause false test results. Therefore, overnight fasting is required for an Insulin Fasting test. The fasting state is also required for accurate insulin sensitivity evaluation, the detection of insulin resistance, and the diagnosis and monitoring of different metabolic disorders, including diabetes.

Q. What can cause high insulin levels in the blood?

High insulin levels in the blood may occur due to sedentary (inactive) lifestyle, obesity, aging, a high carbohydrate diet, family history of diabetes, pregnancy, sleep-related problems, conditions like nonalcoholic fatty liver disease and polycystic ovary syndrome (PCOS), hormonal problems like acromegaly or Cushing’s syndrome, habits like smoking, and due to the use of medicines like steroids, antipsychotics, and HIV medications.

Q. What can cause low insulin levels in the blood?

Low levels of insulin may occur in the blood due to type 1 diabetes, hypopituitarism (low secretion of pituitary hormones), and pancreatic diseases like pancreatitis or pancreatic cancer.

Q. What are the common symptoms of hypoglycemia?

Hypoglycemia, or very low levels of glucose in the blood, can cause symptoms like sweating, nausea, weakness, palpitations, dizziness, hunger, trembling, confusion, irritability, anxiety, blurred vision, irregular heartbeat, seizures, etc.

Q. Does high insulin mean diabetes?

Hyperinsulinemia or a high insulin level means the amount of insulin in the blood is higher than usual. On its own, hyperinsulinemia is not exactly diabetes; however, it is often associated with type 2 diabetes.

Q. What other tests can be prescribed by the doctor in case the results of an Insulin Fasting test are not normal?

Other tests that may be prescribed when the results of an Insulin Fasting test are abnormal include a blood glucose, proinsulin, C-peptide, cortisol, and plasma β-hydroxybutyrate (BHOB) test.

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