Amikacin disaggregates platelet clumps in EDTA blood samples from cats and dogs when added postcollection

BackgroundPseudothrombocytopenia may lead to the erroneous diagnosis of thrombocytopenia, resulting in unnecessary testing and treatment. The addition of exogenous substances to blood samples prior to collection has been shown to mitigate platelet (PLT) clumps in blood samples. Postcollection additives aiming to disaggregate PLT clumps have been largely unexplored. ObjectivesWe aimed to determine if the addition of amikacin to blood samples postcollection aids in the disaggregation of PLT clumps in cats and dogs. MethodsFor this prospective study, EDTA-collected blood samples from 28 cats and 17 dogs were obtained from a hospital population at UC Davis Veterinary Medical Teaching Hospital. Samples had PLT clumps detected on blood smears and thrombocytopenia per analyzer count. Amikacin was added to samples postcollection, and an additional CBC was performed. Flow cytometry was performed to assess PLT-fibrinogen binding in amikacin-treated aliquots. ResultsPLT-clumped samples treated with amikacin significantly increased PLT numbers by 134% and decreased mean platelet volume (MPV) values by 14% (P <= 0.0001) in cats, and increased PLT numbers by 32% (P = 0.04) and increased MPV values by 9% (P = 0.02) in dogs. Mean cell volume (MCV) slightly increased (<4%) for both species. No other CBC parameters were substantially affected by the addition of amikacin. Flow cytometry showed decreased PLT-fibrinogen binding in the majority of cats but was not significant (P > 0.05). ConclusionsAdding amikacin to PLT-clumped blood samples postcollection may be a convenient solution for pseudothrombocytopenia in cats and dogs. Future studies are needed to elucidate the mechanism of amikacin and its effectiveness under different storage conditions. This is the first reported use of amikacin postcollection to disaggregate PLT clumps in blood samples from animals.