A reference range for FI of 1.57 to 16.32 μU/mL has been proposed in Chinese men, but the reference range varies between different ethnicities and genders.34 A FI level above 9μU/mL has been reported to identify 80% of patients with pre-diabetes.35 Although we obtained a cut-off value for fasting insulin, due to large variations in insulin assays, this value of >7.35 should not be generalised to other laboratory sites. Here, INS is linked to diabetes mellitus.