An insulin resistance test is not about a single number, but about a set: fasting glucose, fasting insulin and HOMA-IR, often with HbA1c added. Together they show how well you handle sugar. You can have them drawn without a referral and discuss the result with your GP.
I often get asked which test is the right one. Short answer: not one value, but the combination.
Which blood values do you measure?
Each value tells a different part of the story. Glucose is the snapshot, insulin the early signal, HOMA-IR the combination, and HbA1c the average over weeks. This table sets them side by side.
| Value | What it measures | When useful |
|---|---|---|
| Fasting glucose | Your blood sugar at that moment | Baseline, but often misses the early phase |
| Fasting insulin | How much insulin you need | Early signal, before glucose moves |
| HOMA-IR | Glucose and insulin combined | A measure of resistance |
| HbA1c | Average blood sugar over weeks | Longer trend |
How HOMA-IR is calculated is in fasting insulin and HOMA-IR. The formula lines up well with more complex methods (Matthews, 1985).
Test at home or through your GP?
Both are possible. Your GP usually draws glucose and sometimes HbA1c, but fasting insulin is often not included. If you want insulin and HOMA-IR too, you can have those measured yourself. According to Thuisarts.nl, a raised blood sugar belongs with your GP for the next steps anyway.
For a panel with glucose, insulin and HOMA-IR at once, you can use our insulin resistance (HOMA-IR) test. To choose what you measure yourself, use the custom blood test.
How do you read the result?
A single value is never proof. The combination sketches your sugar handling, and the trend over time says the most. What each picture can mean is covered in the pillar insulin resistance: symptoms, testing and reversing.
My advice: alongside glucose, have insulin measured too if you want an early picture, and discuss a raised HOMA-IR with your GP.
How does a test work?
You usually draw blood fasted, so water only for 8 to 12 hours beforehand. With a panel your blood is taken once, and the lab measures glucose, insulin and possibly HbA1c. HOMA-IR follows from the calculation of your glucose and insulin.
Every result with us includes an assessment by a BIG-registered doctor, who puts your values in context. A result is a starting point for the conversation with your GP, not a diagnosis in itself.
Why measure insulin and not just glucose?
Glucose is the value you get everywhere, but it moves late. In the early phase your body keeps your sugar normal by making more insulin. If you measure glucose alone, you miss that early signal.
Fasting insulin and HOMA-IR show exactly that effort. So measuring insulin adds something glucose alone cannot: a look at how hard your body works to keep your sugar in balance.
Home test or laboratory?
A finger prick at home is handy for glucose, but fasting insulin and HOMA-IR usually need a real blood draw at a collection point. That is why people who want to measure insulin often choose a laboratory test.
When choosing, do not look only at the price, but at what is actually measured. A cheap test without insulin misses the early signal.
Frequently asked questions
Do I have to fast for an insulin resistance test? For fasting glucose and insulin usually yes, so your values are comparable. Follow the instructions with your test.
Does the GP measure insulin by default? Often not. Glucose and sometimes HbA1c are included, but fasting insulin usually has to be requested separately.
How often do you repeat the measurement? That depends on your situation. Many people choose a repeat after a few months to see a trend, in consultation with their GP.
Is HOMA-IR included in a test by default? Not always. HOMA-IR is calculated from glucose and insulin, so the lab or provider must measure both. Check that insulin is in the package.
References
- Matthews DR, Hosker JP, Rudenski AS, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985. PMID: 3899825.
- Selvin E, Steffes MW, Zhu H, et al. Glycated hemoglobin, diabetes, and cardiovascular risk in nondiabetic adults. New England Journal of Medicine. 2010. PMID: 20200384.
- Thuisarts.nl. I have a raised blood sugar (prediabetes). Accessed 2026.
Disclaimer
Every blood test result includes a professional assessment from a BIG-registered doctor. This article gives general information and is not a substitute for medical advice. For treatment decisions, discuss your results with your GP.
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