An immunoassay was used to determine I-FABP levels in 48 individuals at high risk of Me-Is due to lactic acidosis > 4 mmol/L and interleukin (IL)-6 > 600 pg/mL: 6 patients with confirmed Me-Is (cMe-Is), 18 patients with suspected Me-Is (sMe-Is), and 24 patients a in propensity score-matched control group. This evidence concerns the gene FABP2 and lactic acidosis.