Fasting Insulin * Fasting Glucose / 450 for Mass units and Fasting Insulin * Fasting Glucose / 22.5 for Molar units
The HOMA IR predicts insulin resistance.
The HOMA IR is not a perfect way of predicting resistance, but is often used as a surrogate. A score < 3 suggests no resistance. A score between 3 and 5 suggests moderate resistance. A score > 5 suggests severe resistance.