Proposal for fasting insulin and HOMA-IR reference intervals based on an extensive Brazilian laboratory database.

Objective: Fasting insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) index are relatively simple and reliable noninvasive markers of insulin resistance (IR). Given the relevance of correctly diagnosing IR, we emphasize the importance of establishing reliable reference intervals (RIs) for these markers. This study aimed to determine the RIs of fasting insulin and HOMA-IR index in adults living in Rio de Janeiro and, secondarily, to verify potential RI differences between sexes.