HOMA-IR: Insulin Resistance Index
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) quantifies insulin resistance from a single fasting blood draw. Values above 2.0–2.5 suggest insulin resistance. Both glucose and insulin must be measured while fasting (≥8 hours).
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HOMA-IR Score
Formula: HOMA-IR = (Fasting Glucose mg/dL × Fasting Insulin µIU/mL) ÷ 405
Note: The 405 divisor is used when glucose is in mg/dL. If glucose is in mmol/L, use 22.5 instead.
Note: The 405 divisor is used when glucose is in mg/dL. If glucose is in mmol/L, use 22.5 instead.
HOMA-IR Reference Ranges
These thresholds are widely used clinically but vary slightly by population and lab methodology.
| HOMA-IR Value | Interpretation | Clinical Implication |
|---|---|---|
| < 1.0 | Optimal insulin sensitivity | Minimal insulin resistance |
| 1.0 – 1.9 | Normal range | Acceptable; monitor if risk factors present |
| 2.0 – 2.9 | Early insulin resistance | Lifestyle intervention indicated |
| 3.0 – 4.9 | Moderate insulin resistance | Pre-diabetes / metabolic syndrome likely |
| ≥ 5.0 | Significant insulin resistance | High risk; evaluate for T2DM, PCOS, NAFLD |
Associated conditions: Type 2 diabetes, pre-diabetes, polycystic ovary syndrome (PCOS), non-alcoholic fatty liver disease (NAFLD/MASH), metabolic syndrome, and cardiovascular disease risk.
Limitations: HOMA-IR is a research/screening tool. It is not a diagnostic test, and results vary by ethnicity, age, and assay. Insulin assays are not standardized across labs.
Limitations: HOMA-IR is a research/screening tool. It is not a diagnostic test, and results vary by ethnicity, age, and assay. Insulin assays are not standardized across labs.
⚕️ Clinical note: HOMA-IR requires fasting conditions (≥8 hours). Insulin assays vary significantly between laboratories — use the same lab for serial measurements. HOMA-IR is a screening index, not a definitive diagnostic test. Clinical decisions should incorporate full metabolic panel, history, and clinical judgment. Based on the original HOMA model (Matthews DR et al., Diabetologia 1985;28:412–419).