The diagnosis of scrub typhus is hampered due to its nonspecific clinical presentation, poor awareness and insufficient evidence on the ...ArticleAuthorsMetricsCommentsMediaCoverageReaderComments(0)FiguresFiguresAbstractDiagnosisofscrubtyphus,causedbythebacteriumOrientiatsutsugamushi,ischallengingbecauseoftheoverlapofitsnon-specificsymptomswithotherinfectionscoupledwiththelackofsufficientdataontheperformanceofdiagnostictests.Earlydiagnosisofscrubtyphusiscrucialtoimproveoutcomesandthisstudyevaluatesthediagnosticperformanceofvarioustests.Thepresentstudyaimsatassessingtheaccuracyofvariousrapiddiagnostictests,serologictests,andnucleicacidamplificationmethodsonwell-characterizedpatientsamples.AdultpatientswithacutefebrileillnessandmanifestationssuggestiveofscrubtyphusconfirmedbypositivePCRintheblood,escharortissuewerecharacterizedascases.Patientswithacutefebrileillnessandaconfirmedalternateetiologysuchasculture-confirmedtyphoid,smear/PCRpositiveformalaria,PCR/NS1antigenpositivefordengue,PCRpositiveforinfluenza,PCR/MATpositiveforleptospirosis,PCRpositiveforspottedfeverwerecharacterizedascontrolswithotherinfections.Thehealthycontrolsconsistedofsubjectsfromthesamegeographicregion.Weperformedthefollowingtestsonbloodsamplesforscrubtyphusandcalculatedthesensitivity,specificity,positivepredictivevalue,andnegativepredictivevalue:(1)QuantitativerealtimePCRusing47kDagene(qPCR);(2)ConventionalPCRusing56kDagene(cPCR);(3)Loop-mediatedisothermalamplificationassay(LAMPassay);(4)Immunofluorescenceassay(IFA);(5)Enzyme-linkedimmunosorbentassay(ELISA);(6)Weil-Felixtest(WFtest);and(7)ImmunochromatographicRapidDiagnosticTest(RDT).Amongthe316participants,158hadconfirmedscrubtyphus(cases)and158werecontrols.ELISAandRDTdetectingOrientiatsutsugamushispecificIgMantibodieshadexcellentdiscriminativepotentialwithsensitivitiesandspecificitiesof92%,94%and92%,92%respectively.ThesensitivityandspecificityofIFAwerefoundtobe95%and74%respectively.IgMserologyhadafalsepositivityrateof8%withotheracutefebrileill