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Insulin Blood test –A Complete Procedure


An insulin blood test measures the level of insulin in the blood. Insulin is the hormone that converts sugar, also called glucose, from the bloodstream into the cells. The glucose in the bloodstream comes from food and drinks and serves as the body’s primary energy source.

Insulin plays a major role in maintaining glucose levels. If the glucose level is too high or low, it may cause different health issues. Abnormal glucose levels include:

  • Hyperglycaemia

When the blood glucose level is higher-than-normal, you are hyperglycaemic. It occurs when your body doesn’t produce enough insulin or insulin isn’t sufficient to send glucose into the cells, causing glucose to remain in the blood.

  • Hypoglycaemia

When the blood glucose level is low, you are hypoglycaemic. It occurs when the body releases excess insulin into the blood, sending more glucose into the cells. This leaves less glucose in the bloodstream.

The most common cause of an abnormal blood glucose level is diabetes. Two types of diabetes affect people. They include:

  • Type 1 diabetes

Type 1 diabetes causes the body to produce little or no insulin, leading to hyperglycaemia.

  • Type 2 diabetes

In type 2 diabetes, the body can produce insulin, but the cells respond poorly to the insulin, causing the cells not to take up enough glucose from the blood. This causes insulin resistance.

Insulin resistance usually occurs before type 2 diabetes. Insulin resistance causes more production of insulin to supplement the ineffective insulin. The excess insulin in the blood leads to hypoglycaemia, and insulin resistance gradually worsens. 

Over time, insulin resistance reduces the body’s ability to produce insulin. As insulin level reduces, the level of blood sugar increases. If the blood sugar levels do not normalise, type 2 diabetes occurs.

Diagnosing diabetes may involve an insulin blood test, also called fasting insulin test in the UK, total and free insulin, and insulin serum.

Why is an insulin blood test necessary?

An insulin blood test is necessary for the following.

  • To monitor and diagnose insulin resistance
  • To find the cause of hypoglycaemia
  • To check if for a tumour in the pancreas called insulinoma. If you have removed the tumour, the test will help to check if the procedure was successful

The doctor may order insulin testing alongside other tests to help monitor or diagnose type 1 diabetes. These tests include haemoglobin AIC and glucose testing.

Why will I need an insulin blood test

Your doctor may order an insulin blood test if you have hypoglycaemia symptoms. The symptoms include:

  • Trembling
  • Extreme hunger
  • Sweating
  • Confusion
  • Blurred vision
  • Dizziness
  • Irregular heartbeat

You may need other tests like a blood glucose test to be certain you have low blood sugar.

What happened during an insulin blood test?

The healthcare provider will collect your venous blood sample with a small needle. After inserting the needle, the provider will draw a small amount of blood into the vial or test tube. You may feel slight prick when the needle enters your body, and your provider removes it.

How do I prepare for the test?

Before your insulin blood test, you need to fast for at least eight hours before your test.

What are the risks of this test?

The insulin blood test has no significant risk. When your provider inserts the needle, you may experience slight bruising or pain, but these symptoms subside quickly.

What does the result mean?

If your insulin level is higher-than-normal, it indicates any of these conditions.

  • Hypoglycaemia
  • Type 2 diabetes
  • Insulinoma or pancreatic tumour
  • Insulin resistance
  • Crushing’s syndrome – an adrenal gland disorder. The adrenal gland produces hormones that breakdown protein and fat

If the insulin level is lower-than-normal, you may have one of these conditions

  • Type 1 diabetes
  • Hyperglycaemia or high blood sugar
  • Pancreatitis – the inflammation of the pancreas

What else do I need to know about an insulin blood test?

Glucose and insulin work together, your doctor may compare your blood glucose and insulin blood test results to make an accurate diagnosis.

Private Blood Tests London offers insulin in blood testing. If you experience symptoms of abnormal blood glucose levels, you can visit our clinic today for an insulin resistance test UK or call 020 7183 0244 to schedule an appointment for your test.