Optimal Reference Interval for Homeostasis Model Assessment of Insulin Resistance in a Japanese Population

The aim of the present study was to establish a reference interval for homeostasis model assessment of insulin resistance (HOMA-IR) in a Japanese population based on the C28-A3 document from the Clinical and Laboratory Standards Institute (CLSI). We selected healthy subjects aged 20-79 years, with fasting plasma glucose < 100 mg/dL, body mass index < 25 kg/m(2) and alanine aminotransferase < 31 U/L. HOMA-IR values were log transformed, values beyond mean ± 3 standard deviations (SD) were truncated, and the mean ± 2 SD of log HOMA-IR values were taken as the upper and lower reference limits of HOMA-IR. We selected 2173 subjects as reference individuals, and 2153 subjects were used for analysis. The reference interval for HOMA-IR was established as between 0.4 and 2.4. This represents the first reference interval study for HOMA-IR that applies the stringent CLSI C28-A3 document. HOMA-IR ≥ 2.5 should be considered a reasonable indicator of insulin resistance in Japanese. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00113.x, 2011).