Selected blood characteristics (e.g., lipemia), or hemoglobin-based solutions administered to the patients interfere with co-oximetry readings (22); although methemoglobin values were retrospectively retrieved, the role of such interferences was minimal, as lipemic samples are routinely discarded by our laboratory personnel, and blood substitutes were not used in the enrolled dogs. This evidence concerns the gene HBG2 and hyperlipidemia.