Table 2

Thresholds for diagnosis of diabetes and insulin resistance

Fasting blood glucose (mmol/l)Fasting insulin (IU/l)HOMA-IRPeak insulin (IU/l)2-H blood glucose (mmol/l)
Diabetes mellitus≥7>11.1
Impaired fasting glucose5.6–6.9
Impaired glucose tolerance7.8–11.0
Insulin resistanceTanner 1+2: ≥15; tanner 3+4:≥30; tanner 5: ≥20>4.4>100
  • Tanner: tanner stage of puberty (either genital or breast or pubic hair).

  • Insulin levels: fasting insulin is discussed in Section ‘Core investigations’. Peak insulin: no accepted definitions exist for high peak insulin. However, the authors suggest levels >100 IU/l at ≥30 min may be a useful marker for hyperinsulinism.

  • HOMA-IR, Homeostatic model assessment.