Insulin resistance, also known as prediabetes, is a precursor for the development of type 2 diabetes.
Insulin resistance can be present for 5-10 years leading up to a diagnosis, so it makes sense to have it tested.
Yet most doctors will not automatically send you for a blood test for insulin resistance unless you ask.
More commonly they are testing fasting glucose or doing an oral glucose test, which is still important because having elevated blood glucose is also a risk factor and indicator.
But you can test to guage your level of insulin resistance and in my eyes that’s a good thing. If you know your own individual status, you can work on your lifestyle habits so you don’t develop type 2 diabetes.
Blood Test for Insulin Resistance / Prediabetes
Ask your doctor for:
- A fasting glucose test
- A fasting insulin test
Then you can calculate your insulin resistance status using Homeostasis Model Assessment (HOMA) Index.
The HOMA-IR test was developed from “the concept that fasting plasma insulin and glucose levels were determined, in part, by a hepatic-beta cell feedback loop”. Source
So essentially it calculates the balance between pancreatic beta cell function, glucose, and insulin sensitivity. A fasting insulin test is something you may have to pay for yourself but it’s inexpensive and well worth doing so that you can get an insulin resistance calculation.
Fasting Insulin Test
If you use the fasting insulin test on it’s own you can still get a rough indication of your level of insulin resistance.
Insulin resistance status:
- Between 10U/L- 14U/L indicates mild insulin resistance
- Above 14U/L indicates moderate to severe insulin resistance
- The upper limit for normal fasting insulin is 20U/L
But this is not as accurate as the HOMA calculation because it doesn’t compensate for falling insulin and rising blood glucose, the HOMA-IR test does.
Interpreting HOMA-IR Results
So once you have:
- Your fasting glucose numbers
- Your fasting insulin numbers
Here’s how to calculate the HOMA-IR and your level of insulin resistance.
If glucose is measured in mmol/L use this calculation (1):
Fasting insulin mIU/L x fasting glucose mmol/L divided by 22.5
The insulin resistance range:
- Normal <2.0
- Borderline 2.0-2.2
- Moderate IR 2.2-3.0
- Severe IR >3.0
If glucose is measured in mg/dL use this calculation:
Fasting insulin mIU/L x fasting glucose ug/dL divided by 405
The insulin resistance range:
- Normal <3
- Borderline 3-5
- Severe IR >5 Source
Individuals At High Risk For Developing Insulin Resistance
- BMI >25
- Age >40 years
- Waist circumference >40 inches (101 cm) (male)
- Waist circumference >35 inches (88 cm) (female)
- High blood pressure, high triglycerides, low high density lipoprotein cholesterol (HDL-C)
- Latino, African American, Native American, or Asian American heritage
- Family history of diabetes mellitus, high blood pressure, or atherosclerosis
- History of gestational diabetes
- Polycystic ovarian disease
- Acanthosis nigricans Source
It is well worth asking for the blood test for fasting insulin so you can determine your own level of insulin resistance. Then you can be proactive with your diet and lifestyle, because making some changes in that arena can help you avoid a diabetes diagnosis.
Take care of your health
Nutritionist & Health Counselor
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Australian Doctor and The Royal College of Pathologists of Australasia. 2002. Commonsense Pathology: Insulin Resistance.