Insulin resistance: which tests really make sense, what the guidelines say and what they cost

In brief: “insulin resistance” is a mechanism, not a condition on the list of diagnoses. Polskie Towarzystwo Diabetologiczne (Polish Diabetes Association; 2025 recommendations) and Polskie Towarzystwo Leczenia Otyłości (Polish Society for the Treatment of Obesity; 2024) do not recommend measuring insulin or calculating the HOMA-IR index to diagnose it. What really matters for your health is measured using three tests: fasting glucose, an oral glucose tolerance test (OGTT 75 g) and glycated haemoglobin (HbA1c). Insulin and HOMA-IR can be additional tests if your doctor requests them, but they do not replace those three.

What insulin resistance is and why it is not in the guidelines

Insulin is a hormone that “opens up” cells to glucose. Insulin resistance means that the muscles, liver and fatty tissue respond less effectively to it, so the pancreas produces more. Initially, blood sugar levels are normal and insulin levels are raised (hyperinsulinaemia). Over time, the pancreas cannot keep up and blood glucose rises: first into the prediabetes range, then into the type 2 diabetes range. This is how PTLO (Polskie Towarzystwo Leczenia Otyłości — Polish Society for the Treatment of Obesity) describes it in its 2024 recommendations, identifying insulin resistance as the main mechanism behind disorders of carbohydrate metabolism in people with abdominal obesity.

This is precisely why the guidelines do not define “insulin resistance” as a separate diagnosis with laboratory thresholds. Instead, they define its consequences, which can be measured reliably and reproducibly: prediabetes and diabetes.

Who should get tested

According to the 2025 recommendations from PTD (Polskie Towarzystwo Diabetologiczne — Polish Diabetes Association), testing for disorders of carbohydrate metabolism should be carried out:

• once every 3 years in everyone over the age of 45,
• once a year, regardless of age, if there is at least one risk factor: a BMI of 25 or more or a waist circumference of at least 80 cm (women) or 94 cm (men), diabetes in a parent or sibling, low physical activity, previously diagnosed prediabetes, previous gestational diabetes or having given birth to a baby weighing over 4000 g, hypertension, lipid disorders, polycystic ovary syndrome (PCOS), or cardiovascular disease.

Symptoms that make earlier testing worthwhile include sleepiness after meals, cravings for sweet foods that are difficult to control, weight gain around the waist, darkened skin on the back of the neck and in the armpits (acanthosis nigricans), and irregular menstrual cycles in women.

Which tests make sense: the three that count in the guidelines

In addition, if you are overweight or have obesity, PTLO recommends the following at the same sample collection visit: a lipid profile (cholesterol), uric acid, thyroid-stimulating hormone (TSH), ALT and AST, creatinine with eGFR, a full blood count and urinalysis. Insulin resistance rarely occurs alone: it is usually accompanied by lipid disorders and fatty liver disease.

Insulin and HOMA-IR: what they can and cannot tell you

Fasting insulin and the HOMA-IR index, calculated from it together with glucose (glucose [mg/dl] × insulin [µU/ml] / 405), are popular online, but the guidelines are sceptical about them for three reasons:

1. No standard reference range. Laboratories provide indicative thresholds (usually around 2.0-2.5), but no Polish or international scientific society has established a value above which insulin resistance is diagnosed. The chapter on diagnosing disorders of carbohydrate metabolism in the PTD 2025 recommendations does not mention insulin or HOMA-IR at all.
2. High variability. The insulin result depends on the method used by the laboratory, the time of day, stress, sleep, infection and what you ate the previous day. Two measurements in the same person can differ by several tens of per cent.
3. It does not change management. Whether your HOMA-IR is 1.8 or 3.2, the recommendation is the same: weight loss, physical activity and blood glucose monitoring. The 2023 international PCOS guidelines state explicitly that available insulin assays “are of limited clinical relevance and are not recommended in routine care”.

When insulin testing does make sense: when a doctor (an endocrinologist or diabetologist) requests it for a specific purpose, for example if hyperinsulinism is suspected, when investigating hypoglycaemia or as part of an insulin response test. The insulin response test with a 75 g glucose load is for people already under specialist care, not a “first-step” test.

How to prepare

• On an empty stomach: 8-12 hours without food; water is allowed. Coffee, chewing gum and cigarettes affect the result.
• For 3 days before the OGTT, eat normally (do not restrict carbohydrates, as this makes the test less reliable). On the day of the test, arrive in the morning; after drinking the glucose solution, sit quietly for 2 hours at the collection point.
• Do not have an OGTT during an infection, after a sleepless night or if you did strenuous exercise the day before.
• If you take metformin and the test is intended to rule out diabetes, PTD recommends stopping the medicine at least a week beforehand, but only with your doctor’s agreement.
• HbA1c does not require fasting, but it is not suitable for diagnosis if you have anaemia, are pregnant or have certain blood disorders.

Waiting times and what to do with your result

Glucose and OGTT: results on the same or the next working day. HbA1c and insulin: usually 1-2 working days. You download your result online. The result report is issued in Polish.

If your fasting glucose or OGTT result falls within the prediabetes range, do not wait for “confirmation of insulin resistance”. This is already the time to act: see your POZ (podstawowa opieka zdrowotna — primary healthcare) doctor, make a plan to reduce your body weight by 5-7%, do 150 minutes of moderate physical activity a week and have a follow-up check in 6-12 months. If your glucose result is 126 mg/dl or more, your doctor will repeat the test on another day, because diabetes is diagnosed on the basis of two measurements.

Frequently asked questions

My HOMA-IR is 2.8 and my glucose is normal. Do I have insulin resistance?

You have a raised index for which there is no agreed reference range. OGTT and HbA1c will give a more reliable answer. If both are within the normal range and you are overweight, the approach is still the same: weight loss and physical activity. If you have PCOS, OGTT is the test of choice and is repeated every 1-3 years.

Can I have these tests without a referral?

Yes. Glucose, OGTT, HbA1c, lipid profile and insulin tests are available privately at over 700 collection points in Poland. The only practical exception is that an OGTT requires 2 hours at the collection point, so ask whether your chosen location performs the test on your preferred day.

Which is better to start with: OGTT or HbA1c?

If you have symptoms or risk factors: OGTT, because it detects impaired glucose tolerance that HbA1c and fasting glucose do not pick up. HbA1c is more convenient (no fasting and no 2-hour stay at the collection point) and useful for monitoring, but the PTD 2025 recommendations treat it as a signal to perform an OGTT, not as a replacement.

Sources

• Polskie Towarzystwo Diabetologiczne (Polish Diabetes Association), Zalecenia kliniczne dotyczące postępowania u osób z cukrzycą 2025 (Clinical recommendations for the management of people with diabetes 2025), chapter 1 “Principles for diagnosing disorders of carbohydrate metabolism”, pp. 13-16. ptdiab.pl (PDF)
• Polskie Towarzystwo Leczenia Otyłości (Polish Society for the Treatment of Obesity), Zalecenia kliniczne dotyczące postępowania u chorych na otyłość 2024 (Clinical recommendations for the management of patients with obesity 2024), pp. 17-20 (screening tests, insulin resistance as a mechanism). ptlo.org.pl (PDF)
• Teede H.J. et al., Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome, Human Reproduction 2023; 38(9): 1655-1679, recommendations 1.9.2, 1.9.9, 1.9.10, 1.9.12. academic.oup.com