On 2017 Jun 19, Stuart RAY commented:

In response to a query regarding the method used to measure insulin concentration (to calculate HOMA-IR), Dr. Kernan referred me to Viscoli CM, 2014, which states: "The Linco (St. Charles, MO) human insulin-specific radioimmunoassay (RIA) was used at the laboratories in North America and Australia to measure circulating insulin concentrations. Because this assay was not available at the laboratories in Europe and Israel, the Linco animal serum-free enzyme-linked immunosorbent assay was used and results converted to RIA values by means of an internal LINCO correlation equation (insulin RIA [μU/mL] = 1.1056 × (insulin enzyme-linked immunosorbent assay [ulU/mL]) + 2.1494)."

On 2017 Jun 19, Stuart RAY commented:

In response to a query regarding the method used to measure insulin concentration (to calculate HOMA-IR), Dr. Kernan referred me to Viscoli CM, 2014, which states: "The Linco (St. Charles, MO) human insulin-specific radioimmunoassay (RIA) was used at the laboratories in North America and Australia to measure circulating insulin concentrations. Because this assay was not available at the laboratories in Europe and Israel, the Linco animal serum-free enzyme-linked immunosorbent assay was used and results converted to RIA values by means of an internal LINCO correlation equation (insulin RIA [μU/mL] = 1.1056 × (insulin enzyme-linked immunosorbent assay [ulU/mL]) + 2.1494)."