In vitro-induced Heinz bodies showed no impact on feline reticulocyte haemoglobin content measurement using the Advia 2120i analyser

ObjectivesReticulocyte haemoglobin content (CHr) is a promising tool for evaluating iron status in dogs; however, its usefulness in cats varies. Heinz bodies interfere with haematological analyses on the Advia 120/2120i analyser (Siemens Healthineers), but the effect of Heinz bodies on CHr measurement in feline blood samples is unknown.MethodsIn an analytical intervention study, CHr concentration was measured pairwise in 30 feline blood samples with and without Heinz bodies chemically induced in vitro using 1-acetyl-2-phenylhydrazine (APH).ResultsThe percentage of Heinz bodies and the amount of Heinz body material were assessed by microscopy after staining with New Methylene Blue, and both increased significantly after in vitro APH incubation. After incubation, CHr levels decreased significantly in both samples without APH and in APH-treated samples, but no significant difference was detected between the samples with and without APH.Conclusions and relevanceIn vitro<i>-</i>induced Heinz bodies did not impact CHr levels. Explaining the lesser diagnostic utility of CHr measurements in cats compared with dogs as an effect of Heinz bodies is therefore not substantiated by this in vitro study. Accordingly, variations in feline patient populations and varying definitions of iron deficiency in previous studies are likely the main explanations for the lesser diagnostic utility of CHr measurements in cats.