Calculate Matsuda Insulin Sensitivity Index
Enter paired glucose and insulin values from an oral glucose tolerance test (OGTT). Include fasting (0 min) and at least one post-load time point.
What is the Matsuda Index?
The Matsuda Index is a widely used estimate of whole-body insulin sensitivity derived from OGTT data. It combines fasting and post-glucose values for both glucose and insulin, making it more informative than fasting-only markers.
Equation
- G0 = fasting glucose (0 min)
- I0 = fasting insulin (0 min)
- Gmean = mean glucose across available OGTT time points
- Imean = mean insulin across available OGTT time points
In this calculator, glucose is internally converted to mg/dL and insulin to µU/mL before calculation.
How to use this calculator correctly
1) Enter paired values
Each time point must have both glucose and insulin. If one is missing, the pair cannot be used.
2) Include fasting and post-load points
Fasting values (0 min) are required. For best accuracy, include 30, 60, 90, and 120-minute values when available.
3) Verify units
Unit mismatch is a common source of error. Always confirm the units reported by your lab before entering data.
How to interpret your result
There is no single universal cutoff across all populations, study designs, and assays. In general, lower values suggest lower insulin sensitivity (greater insulin resistance), while higher values suggest better insulin sensitivity.
- < 2.0: often consistent with marked insulin resistance
- 2.0–3.0: reduced insulin sensitivity
- 3.0–4.5: moderate/typical range in many datasets
- > 4.5: relatively higher insulin sensitivity
These are practical educational ranges, not a diagnosis. Clinical interpretation should consider history, exam, medications, and lab context.
Common pitfalls
- Mixing glucose units (mmol/L vs mg/dL)
- Mixing insulin units (pmol/L vs µU/mL)
- Using non-paired values at a time point
- Interpreting one index without overall metabolic context
Clinical and research context
The Matsuda Index is often used in endocrinology and metabolism research as a practical surrogate for insulin sensitivity. It does not replace gold-standard methods like the hyperinsulinemic-euglycemic clamp, but it is valuable when OGTT data are already available.
If your goal is risk stratification or treatment planning, discuss results with a qualified clinician who can interpret your full metabolic picture.