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Table 2 Formulae for the most commonly used simple indices of insulin resistance derived from fasting specimens and other specimens taken in the context of an oral glucose tolerance test (GTT).

From: Selection of the appropriate method for the assessment of insulin resistance

Index Formula Reference
GTT derived indices:
ISI-gly 2/[(INSp × GLYp)] + 1 [74]
ISI (composite) 1000/√{[fasting glucose (mg/dL) × fasting insulin (μU/mL)] × [mean glucose × mean insulin]} [21]
Fasting sample indices:
HOMA-IR Fasting glucose (mmol/L) ×fasting insulin (mU/L)/22.5 [36]
HOMA2-S HOMA2 calculator version 2.2 [37]
FGIR Fasting glucose (mg/dL)/Fasting insulin (mU/L) [58]
Raynaud 40/Fasting insulin (mU/L) [33]
Reciprocal insulin 1/fasting insulin (mU/L) [34]
QUICKI 1/[log fasting insulin (mU/L) + log fasting glucose (mg/dL)] [46]
FGIR Fasting glucose (mg/dL)/Fasting insulin (mU/L) [58]
  1. Key: GTT, oral glucose tolerance test; HOMA-IR, homeostasis model assessment insulin resistance; QUICKI, quantitative insulin sensitivity check index; FGIR, fasting glucose insulin ratio; ISI (composite), an index of whole-body insulin sensitivity; ISI-gly, insulin sensitivity glycemic index; INSp, insulinemic area; GLYp, glycemic area.