Hemolysis, icterus and lipemia interfere with the determination of Thiobarbituric Acid Reactive Substances (TBARS) and Total Antioxidant Status (TAS) in canine serum.

Abstract Background Oxidative stress has been proved to participate in a plethora of human and canine diseases. Among oxidative stress biomarkers, Thiobarbituric Acid Reactive Substances (TBARS) and Total Antioxidant Status (TAS) are two of the most widely used. Pre-analytical factors are highly relevant to obtain accurate results in these assays. Hemolysis, icterus and lipemia (HIL) are among the most frequent sources of pre-analytical errors in the laboratory, but limited information is available on the considerations for canine specimens. Hence, the objective of this study was to assess the potential interferences due to HIL on the determination of TBARS and TAS in canine serum. Methods Dilutions of canine pooled serum samples were prepared with increasing concentrations of hemolysate, bilirubin and a synthetic lipid emulsion. TBARS and TAS were determined, and biases from the control value due to the interferents were calculated. Results Hemolysis, icterus and lipemia induced significant interferences on TBARS and TAS, to a variable extent depending on the biomarker and interferent. TBARS seemed the most vulnerable method to interferences in this study. Slight hemolysis, moderate icterus and slight lipemia induced significant deviations of TBARS value, exceeding the acceptable interference threshold. TAS assay was also affected by HIL, but to a lesser extent compared to TBARS. Significant biases from TAS control value were observed when icterus was moderate, and hemolysis and lipemia were marked. Conclusions TBARS and TAS assays are widely used for oxidative stress evaluation. However, the literature on the interference of HIL on these biomarkers in canine serum is scarce. In light of our results, we conclude that hemolyzed, icteric and lipemic specimens are not suitable for TBARS and TAS determination in canine serum. Our findings seem of considerable practical utility, as a simple visual inspection would be sufficient for discarding these specimens.