Association of positive direct antiglobulin test (DAT) with nonreactive eluate and drug-induced immune hemolytic anemia (DIHA)

Background and Objectives: Drug-induced immune hemolytic anemia is a rare condition that occurs primarily because of drug-induced antibodies, either dependent or independent and positive direct antiglobulin test. Our aim was to evaluate the association of positive DAT with nonreactive eluate and DIHA. Materials and Methods: From 2014–2018, we evaluated 159 patients who presented positive DAT with a nonreactive eluate. Laboratory and clinical analyses were performed including HIV, HBV and HCV testing. All patients were exposed to the following drugs: Dipyrone in 63.5 %, Furosemide in 28.9 %, Metoclopramide in 34.6 % and Ondansetron in 41.5 %. Results: Results of DAT showed IgG in 125 (78.4 %) patients and C3d in 24 (15.1 %) with reactions varying from 1+ to 4+. HIV test was positive in 10 (16.1 %) patients, HBV was positive in 3 (4.7 %) and HCV was positive in, 1 (1.5 %). There was no clinical significance when the parameters of hemoglobin, hematocrit, reticulocytes and LDH were evaluated, only a slight increase in bilirubin, especially, in patients with positive DAT reacting 3+/4+ due to IgG and C3d sensitization. Clinical evaluations showed that all patients were asymptomatic. Conclusions: The association of drugs with positive DAT can be a challenge to transfusion services and immunohematology reference laboratories. There was no evidence of any case of severe hemolysis with clinical repercussion through the clinical and laboratory findings analyzed with the drugs associated with positive DAT. Dipyrone and Furosemide have already been associated with DIHA but there are no studies reporting the association of Metoclopramide and Ondansetron with DIHA.