Insulin resistance test: what your blood work shows

There is no routine insulin resistance test, but fasting glucose, triglycerides, HDL and liver enzymes already leave signals, if you read them together.

Insulin resistance test: what your blood work shows

6 min - BioSense Team - 2026-10-20

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Insulin resistance can set in years before type 2 diabetes is diagnosed. Throughout that time, blood glucose can stay normal. No routine insulin resistance test exists, but several signals already appear on standard blood work, provided they are read together and followed over time.

Your fasting glucose has been normal for years, and yet you wonder whether all is well on the metabolic side. The process that leads to type 2 diabetes begins well before blood glucose goes out of range, and it leaves traces in ordinary lab results.

What is insulin resistance?

Insulin is the hormone that allows sugar to leave the blood and enter the cells. After a meal, the pancreas releases some, and blood glucose comes back down.

Over time, in some people, the cells respond less well to that signal. This is what is called insulin resistance.

The pancreas then compensates by producing more insulin. And as long as it manages to, blood glucose stays normal. That is precisely what makes this period silent: the system is under strain, but the number on the report barely moves.

Blood glucose only starts to rise when the compensation runs out of steam. In the long-term British Whitehall II study, insulin sensitivity was falling steeply in the five years before diabetes was diagnosed, and the authors placed the start of these changes at three to six years before diagnosis. The process has often been under way for a long time by then.

Fasting insulin and HOMA-IR: is there a good insulin resistance test?

Since insulin rises first, why not simply measure it?

The question comes up often, and several websites offer to calculate an index, HOMA-IR, from fasting insulin and fasting glucose. Three things call for caution.

This test does not appear in routine US screening recommendations, which rest on fasting glucose, A1C and the glucose tolerance test. The NIDDK, part of the National Institutes of Health, states that health care professionals may not test for insulin resistance and that the test is primarily used for research studies.

The index was developed for population studies, not for individual interpretation. Its cutoffs are not a matter of consensus, and the values put forward vary appreciably from one publication to the next.

Finally, its formula changes depending on the units used, mg/dL or mmol/L for glucose. A calculation done at home easily gives a wrong result.

The good news lies elsewhere, and it is simpler. The signals already exist in your usual blood work.

Insulin resistance: what your blood test already shows

Four items from a routine checkup carry the trace of insulin resistance. None is enough on its own; it is their combination that is informative.

Blood glucose rising inside the normal range

This is the earliest and most overlooked signal. A fasting glucose going from 86 to 92 and then 98 mg/dL (4.8, 5.1 and 5.4 mmol/L) over five years stays within the normal range at every check. Taken in isolation, each measurement is reassuring. Put in series, the trajectory tells a different story.

This kind of trend only shows up if you have your earlier blood tests. A single report cannot reveal it.

The triglyceride and HDL pair

Insulin resistance alters fat metabolism in a characteristic way: triglycerides tend to rise while HDL, often called good cholesterol, tends to fall.

Research has used the ratio between these two markers as an indirect indicator in large populations.

One important caveat before you reach for your calculator: the cutoffs published for this ratio vary with sex and ancestry, and with the units used, since a ratio in mg/dL and a ratio in mmol/L are not the same number. What matters is not a figure to calculate, but the fact that these two lines of your lab report are read together, and that their joint trend is followed over time.

The liver markers: GGT and ALT/AST

Insulin resistance promotes the buildup of fat in the liver, a condition now called metabolic dysfunction-associated steatotic liver disease (MASLD, formerly NAFLD). It can show up as a moderate rise in GGT or in liver enzymes, without excessive alcohol use. Normal liver enzymes do not rule it out, however.

This condition is common: the American Association for the Study of Liver Diseases (AASLD) estimates that it affects 25% to 30% of adults, and US estimates suggest one-third to two-thirds of people living with type 2 diabetes.

Waist circumference

This is not a blood test, but it is part of a prevention checkup and among the most informative items. Deep abdominal fat is closely linked to insulin resistance and is a bigger risk factor for heart disease than fat elsewhere in the body, according to the National Heart, Lung, and Blood Institute (NHLBI).

Two people of the same weight can be in very different metabolic situations depending on how that fat is distributed.

Key point - Blood glucose rising inside the normal range, triglycerides going up while HDL comes down, liver markers discreetly raised, increased waist circumference. These four items come from a routine checkup. Reading them together, and above all their trend, is more informative than any additional test.

No additional test is needed to spot these signals. What is missing is bringing your successive blood tests together and reading these markers as a whole rather than line by line. That is exactly what BioSense does: every biomarker explained, set back in your personal situation, and followed from one test to the next. Your data is hosted on servers located in France.

[→ Import my blood tests](/en/onboarding/upload)

Insulin resistance and metabolic syndrome

When several of these items coexist in the same person, doctors speak of metabolic syndrome.

It is not a disease but a cluster of items which, taken together, increase the risk of developing type 2 diabetes and cardiovascular disease. A harmonized international definition, endorsed by the American Heart Association and the NHLBI among others, sets out its precise criteria, which rest on waist circumference, blood glucose, triglycerides, HDL and blood pressure.

We set out these criteria in detail in our article on the markers to watch from age 50. One point is worth underlining here: this grid is for a doctor who has your complete record. Working it out yourself on the back of an envelope often leads to hasty conclusions, in either direction.

How to reverse insulin resistance: what the trials show

Insulin resistance can improve, particularly when it is spotted early. That is what sets this period apart from the one that follows the onset of diabetes.

The Diabetes Prevention Program, a large US trial, compared a structured lifestyle intervention with metformin in people at high risk. Over about three years, the lifestyle intervention reduced the occurrence of diabetes by 58%, against 31% for the drug. Follow-up of these participants, published in 2025, shows that the effect persists more than two decades later: a 24% reduction for lifestyle and 17% for metformin, or about three and a half more years without diabetes for the lifestyle group (median). In China, the Da Qing study observed, thirty years after the intervention, fewer cardiovascular events and lower mortality.

The changes studied in these trials concerned regular physical activity, diet and a moderate reduction in weight. Nothing spectacular, but results measured in several thousand people and followed for years. The American Diabetes Association now recommends referring people at high risk to a prevention program of this kind, and the CDC recognizes such programs in the US.

The discussion about what suits you personally is one to have with your doctor, who will take your full situation into account.

Key point - Spotted early, insulin resistance can improve. A landmark trial measured a 58% reduction in the occurrence of diabetes thanks to a lifestyle intervention, with a benefit that holds up over time.

The BioSense method

In most situations, the information needed already appears in the tests your doctor has ordered. BioSense brings them together, explains them and follows their trend: four lines of ordinary blood work, read together, say more than an additional test interpreted in isolation.

*ChatGPT answers you. BioSense knows you.* *BioSense, your prevention companion.* BioSense does not provide a diagnosis and does not replace your doctor. It is a prevention companion that helps you understand, ask the right questions and act day to day.

Insulin resistance: three questions to ask your doctor

These three questions move the appointment from today's result toward your trajectory:

  • Comparing my blood tests from recent years, is my fasting glucose stable or rising, even within the normal range?
  • Are my triglycerides and my HDL moving in a direction that deserves attention?
  • Given my waist circumference, my family history and these results, are there steps to consider right now?

Bring your earlier blood tests. On this particular subject, the trend is far more informative than today's result.

Frequently asked questions

What is the best test for insulin resistance?

There is no single routine test: spotting it relies mainly on fasting glucose, A1C, triglycerides, HDL, liver enzymes and waist circumference, read together. According to the NIDDK, a direct insulin resistance test is used primarily in research.

What is a normal HOMA-IR score?

No value is agreed on: published cutoffs vary from one paper to another. This index was designed for population studies, not for interpreting an individual result.

Can you have insulin resistance with normal blood sugar?

Yes, that is even the rule at the start: the pancreas compensates by producing more insulin, and blood glucose stays within the usual values. It only rises when that compensation runs out of steam.

Can insulin resistance be reversed?

It can improve, especially if it is spotted early. Physical activity, diet and moderate weight loss reduced the onset of diabetes in the large trials. Your doctor helps you choose what suits your situation.

*This article is strictly informational and constitutes neither medical advice nor a diagnosis. For any question about your health, consult your doctor.*

Import your reports, even older ones, and receive a plain-language reading of each biomarker, set back in your personal situation and followed from one test to the next. Your data is hosted on servers located in France.

[→ Import my blood tests](/en/onboarding/upload)

Sources and methodology

International

United States

United Kingdom

*Methodological note: this article deliberately offers no calculation to do yourself, neither for the HOMA-IR index nor for the ratio between triglycerides and HDL, because published cutoffs vary with populations, sex and units of measurement.*

*BioSense methodology: our content is based on guidance from US authorities and medical societies (such as the USPSTF, CDC, NIH, FDA, ACC/AHA and ADA), UK bodies (NICE, NHS), European societies and the WHO. Sources are listed by country, and differences between countries are stated when they matter.*

Further reading