How to Test for Insulin Resistance: FAQ Guide

Published January 16, 2025

Insulin resistance is a condition that affects your body’s ability to regulate glucose (or blood sugar)¹. Researchers have found that more than 40% of Americans 18 to 44 have insulin resistance,² which can lead to pre-diabetes or diabetes without proper treatment and management.³

That’s why it’s important to understand how to check for insulin resistance. This article discusses what you need to know about insulin resistance testing — why you should get tested, what test options are available, what your test results mean, and why Quest is the right choice for helping you get tested.

Why test for insulin resistance?

It’s better to identify and address insulin resistance early, if possible, before it can develop into pre-diabetes (consistently elevated blood sugar but not yet high enough to be diagnosed as diabetes)⁴ or Type 2 diabetes (a chronic condition in which the body can’t use insulin properly due to persistently high blood sugar). Type 2 diabetes can have serious effects on many systems of the body, including your risk for heart disease, kidney disease, and stroke.⁵

If you have insulin resistance, you may not have any symptoms at first if your pancreas can create enough insulin to keep your blood sugar in check. But over time, the cells that make insulin can wear out. This can lead to high blood sugar and the development of pre-diabetes or Type 2 diabetes.

Some people with insulin resistance may notice symptoms such as:

• Fatigue, especially after eating
• Difficulty losing weight
• Increase hunger or sugar cravings
• Darkened skin, often the neck or armpits (acanthosis nigricans)⁴

What blood test shows insulin resistance?

There are several blood tests for insulin resistance. Quest’s Insulin Resistance Test Panel tests for the levels of intact insulin in the blood. Many other commercially available tests measure both intact insulin molecules and insulin fragments, so they can return artificially high results.⁶

Quest also tests for levels of C-peptide (a hormone the body makes during the process of making insulin). C-peptide doesn’t affect blood sugar levels. However, it does stay in the blood longer than insulin, so it can help measure how much insulin your body is making.⁷

Although Quest doesn’t include them in its Insulin Resistance Test Panel, other insulin resistance testing options include:

• Oral glucose tolerance test: This test involves taking samples of the blood one and two hours after drinking a glucose solution to see how the body processes glucose⁸
• Hemoglobin A1C test: This test measures the average amount of blood sugar during the previous three months⁹

How to prepare for your insulin resistance test

You will need to fast for 8 to 12 hours before your insulin resistance test. This is to ensure your blood sugar levels are at the lowest levels they should be.

If you take any medications or supplements, check with your healthcare provider to find whether you should take those before your insulin resistance test.

What do your insulin resistance test results mean?

For your insulin resistance test at Quest, based on your intact insulin and c-peptide levels, you’ll receive an overall insulin resistance score*. This shows how likely it is that you have insulin resistance:

• If your score is less than 33, you have normal sensitivity to insulin (i.e., no insulin resistance)
• If your score is between 33 and 66, you are four times more likely to have insulin resistance
• If your score is above 66, you are 15 times more likely to have insulin resistance

If you do have insulin resistance, you may want to discuss more regular checks of your blood sugar levels with your healthcare provider. You’ll also have an opportunity to discuss your results with an independent doctor after your test.

Why buy insulin resistance tests online from Quest?

Early insulin resistance testing can give you the facts you need so you can take steps to reduce your risk for pre-diabetes and Type 2 diabetes. That’s why Quest offers convenient insulin resistance testing you can purchase online. You don’t need a doctor’s visit. Just buy your test, schedule your sample collection, and get your results.

Quest offers testing in more than 2,000 locations. Or you can schedule sample collection in your own home (if available in your area). Find out whether you have insulin resistance by getting tested.

Buy your insulin resistance test

No doctor visit is required to buy your own lab test at questhealth.com. PWNHealth and its affiliates review your purchase to ensure it is medically appropriate before submitting the test order for processing. PWNHealth also reviews your test results and will contact you directly if they require prompt attention. Included in each purchase is the option to discuss your test results with an independent physician; however, you are also encouraged to speak with your primary healthcare provider.