BackgroundIdentification of Burkholderia pseudomallei, the cause of melioidosis, using routine methods takes several days. Use of a monoclonal antibody-based immunofluorescent assay (IFA) on positive blood cultures may speed diagnosis.MethodsWe tested the diagnostic accuracy of the IFA on 545 blood cultures positive for Gram-negative organisms at Udon Thani Hospital, Thailand, between June 2015 and August 2016.ResultsSensitivity of the IFA was 100% and specificity was 99.6%. The median decrease in time to pathogen identification between the IFA result and routine methods was 28 h (IQR 25–51), p<0.0001.ConclusionsThe IFA accurately expedites the diagnosis of melioidosis.