Insulin resistance: the early metabolic signal standard screening isn't built to catch
Fasting insulin and glucose, read together through HOMA-IR, can flag insulin resistance years before a routine glucose test. Here is how the testing works and who it is for.
9 min read·27 June 2026
58%
the reduction in progression to type 2 diabetes from structured lifestyle change in the Diabetes Prevention Program
Source: [7]
The Short Answer
It depends, but if you have insulin-resistance risk factors, measuring fasting insulin and glucose together is one of the earliest metabolic signals you can get.Insulin resistance is a state where your cells respond less efficiently to insulin, so your pancreas works harder to keep glucose normal, and it can develop years before a glucose or HbA1c test turns abnormal.[1] Measuring fasting insulin and fasting glucose from one draw lets you calculate HOMA-IR, a simple index of that relationship first described in 1985.[2] It is not part of routine screening and is not a diagnosis on its own, but for people with risk factors such as central weight gain, PCOS, or a family history of type 2 diabetes, it offers an early, modifiable signal to discuss with your GP.[8]
Frequently Asked Questions
Insulin resistance is when your cells respond less efficiently to insulin, so your pancreas makes more of it to keep blood glucose normal. It can be present for years before glucose or HbA1c tests become abnormal, which is why it is sometimes called a silent, early phase of metabolic change.
There is no single test. The usual approach measures fasting insulin and fasting glucose from one blood draw and combines them into HOMA-IR = (fasting insulin in mU/L x fasting glucose in mmol/L) / 22.5. An HbA1c is often added for context. The combination is more informative than glucose alone.
Yes. This is the main reason the test exists. Your pancreas can keep glucose in the normal range by producing extra insulin, so a glucose reading can look fine while insulin is elevated. Measuring insulin and glucose together, through HOMA-IR, can reveal that pattern.
There is no single universal cut-off. Lower values suggest greater insulin sensitivity and higher values suggest more resistance, but the thresholds quoted in research (often around 2 to 2.5) are population-dependent and vary by ethnicity, assay, and laboratory. Read your figure in context with your GP rather than as a strict pass or fail line.
No. Fasting insulin, glucose, and HbA1c can be ordered privately without a GP referral. It is sensible to discuss the result with a health practitioner, who can interpret it alongside your history, glucose, weight, and symptoms.
Disclaimer:This information is educational only and not medical advice. Results should be interpreted by your health practitioner in the context of your symptoms and health history. Treatment decisions should be made with your doctor or specialist.
