title: Inter- and intra-operator variability in the reading of indirect immunofluorescence assays for the serological diagnosis of scrub typhus and murine typhus.
abstract: Inter- and intra-observer variation was examined among six microscopists who read 50 scrub typhus (ST) and murine typhus (MT) indirect immunofluorescence assay (IFA) immunoglobulin M (IgM) slides. Inter-observer agreement was moderate (κ = 0.45) for MT and fair (κ = 0.32) for ST, and was significantly correlated with experience (P = 0.03 and P = 0.004, respectively); κ-scores for intra-observer agreement between morning and afternoon readings (range = 0.35-0.86) were not correlated between years of experience for ST and MT IFAs (Spearman's ρ = 0.31, P = 0.54 and P = 0.14, respectively; P = 0.78). Storage at 4°C for 2 days showed a change from positive to negative in 20-32% of slides. Although the titers did not dramatically change after 14 days of storage, the final interpretation (positive to negative) did change in 36-50% of samples, and it, therefore, recommended that slides should be read as soon as possible after processing.
authors.forename: Rattanaphone
authors.initials: R
authors.lastname: Phetsouvanh
authors.forename: Thaksinaporn
authors.initials: T
authors.lastname: Thojaikong
authors.forename: Phonlavanh
authors.initials: P
authors.lastname: Phoumin
authors.forename: Bountoy
authors.initials: B
authors.lastname: Sibounheuang
authors.forename: Koukeo
authors.initials: K
authors.lastname: Phommasone
authors.forename: Vilada
authors.initials: V
authors.lastname: Chansamouth
authors.forename: Sue J
authors.initials: SJ
authors.lastname: Lee
authors.forename: Paul N
authors.initials: PN
authors.lastname: Newton
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Blacksell
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods / Q000592:standards*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D015588:Observer Variation; D012285:Orientia tsutsugamushi / Q000276:immunology; D012286:Rickettsia typhi / Q000276:immunology; D012612:Scrub Typhus / Q000175:diagnosis* / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D014437:Typhus, Endemic Flea-Borne / Q000175:diagnosis* / Q000453:epidemiology* / Q000276:immunology / Q000382:microbiology; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M