Insulin Resistance Test
Last updated on July 15th, 2016
Insulin is a protein-based hormone that is secreted by the islet cells in the pancreas. When the pancreas senses an increase in blood glucose levels, it releases insulin, which is responsible for putting the glucose into the cells to be used as a type of cellular fuel. Without insulin, the cells would starve from having a lack of energy.
If you have insulin resistance, it means that, while the pancreas is putting out insulin, the cells of the body cannot recognize it and the glucose levels rise in the bloodstream. If the blood sugar becomes too high, it means that you have type 2 diabetes or prediabetes. People with polycystic ovarian syndrome and metabolic syndrome also have insulin resistance.
No one knows why insulin resistance occurs. It is believed to be somewhat related to being obese or overweight; however, people who do not exercise enough can also develop insulin resistance, even if they are not overweight,
The Effects of Insulin Resistance
Rarely would one have any symptoms from having insulin resistance, especially if the disease is in its earliest stages. A person can suffer from insulin resistance for many years and might not know it, particularly if the blood glucose level is still normal.
Insulin resistance is associated with a skin condition called “acanthosis nigricans”. This is a condition in which dark areas of the skin develop on the groin area, the armpits, and in the back of the neck. Insulin resistance tends to get worse over time so that the person eventually shows elevated blood glucose levels. When this happens, it is called type 2 diabetes.
Insulin resistance can also cause damage to the blood vessels. This is completely asymptomatic so you don’t usually know you have it until you get complications, such as a stroke or a heart attack. Insulin resistance naturally leads to type 2 diabetes, which may not have any symptoms either. Only a blood test can show if you have insulin resistance.
The typical symptoms of insulin resistance that has turned into diabetes include the following:
- Increased tiredness or fatigue
- Numbness or tingling of the feet or hands
- Increased frequency of urination
- Feeling hunger even after eating
- Having a great deal of hunger or thirst
Blood work for Insulin Resistance
There is no specific test for insulin resistance but it can be determined indirectly by having your blood drawn. The various blood tests that can be used to test for insulin resistance include the following:
- Hemoglobin A1c test. This is a test to see how “sugar coated” the red blood cells are. When the blood glucose levels are high, the glucose binds to hemoglobin, producing glycated hemoglobin. The hemoglobin A1c test is a measure of the percentage of hemoglobin that is glycated. Elevated levels of hemoglobin A1c can detect insulin resistance by identifying prediabetes or type 2 diabetes. Abnormally high levels of hemoglobin A1c (above 6.5 percent) means that you have insulin resistance and type 2 diabetes. Hemoglobin A1c levels between 5.7 percent and 6.4 percent means that you have prediabetes, while hemoglobin A1c levels at 5.7 or below are considered to be normal levels.
- Fasting Blood Sugar Test. This is a test that measures your blood glucose level after you have fasted for a minimum of 8 hours. The blood is drawn and measures the amount of glucose in the bloodstream. Normal fasting blood glucose levels are less than 100 mg/dL. If the fasting blood glucose level is between 100 and 125 mg/dL, it means that you have prediabetes and are at risk for later having type 2 diabetes Any number higher than 125 mg/dL on a fasting basis means that you have type 2 diabetes from insulin resistance.
- Random Blood Testing. You can diagnose insulin resistance just by checking the blood glucose value at any time during the day. When the glucose is checked randomly, a normal blood glucose level should be less than 140 mg/dL. If the random blood glucose test is between 140 and 199 mg/dL, it means you likely have prediabetes. If the random blood glucose level is at least 200 mg/dL or higher, it means you have type 2 diabetes.
- Oral glucose tolerance test. This is a test in which you have a fasting blood glucose test drawn and then drink a hundred grams of glucose in a sugary beverage. The glucose levels are measured at a half hour, one hour, two hours, and three hours after drinking the sugary beverage. Elevated blood sugar levels at any of these stages, means you have prediabetes or type 2 diabetes from insulin resistance.
When should you be checked for insulin resistance and type 2 diabetes?
Every person should have one of the above tests beginning at the age of 40 when the blood is also checked for cholesterol, liver function, and kidney function. This is a part of preventative health screening that should be repeated every 3 to 5 years.
You should be checked earlier for insulin resistance under the following circumstances:
- You have symptoms of insulin resistance
- You have elevated blood pressure (higher than 140/90)
- You are of a certain heritage: African-American, American Indian, Pacific Islander, Asian-American, or Hispanic
- You have a first degree relative (parent, child, or sibling) with type 2 diabetes
- You have low HDL cholesterol levels
- You have high levels of triglycerides
- You do not exercise
- You are overweight or obese
- You had a baby that was at least 9 pounds
- You had gestational diabetes in pregnancy (for women)
- You have polycystic ovarian syndrome
If you are at a high risk for insulin resistance, any one of the above tests should be drawn again every 2-3 years to see if you have developed prediabetes or type 2 diabetes.
Preventing Insulin Resistance
It is possible to prevent type 2 diabetes if you put your mind to it. You need to exercise on a regular basis (at least 150 minutes per week) and you need to eat a low calorie, low fat diet. If you can do these things so that you lose some weight, you may be able to prevent type 2 diabetes and prediabetes.
If you are diagnosed with prediabetes or insulin resistance but do not yet have type 2 diabetes, you can keep type 2 diabetes away by having a healthy diet, losing weight, and exercising regularly.
- Symptoms of Insulin Resistance. http://www.healthline.com/health/diabetes/insulin-resistance-symptoms#Overview1. Accessed 5/21/16.
- Insulin Resistance. https://labtestsonline.org/understanding/conditions/insulin-resistance/start/1. Accessed 5/21/16.