Rattanaphone PhetsouvanhThaksinaporn ThojaikongPhonlavanh PhouminBountoy SibounheuangKoukeo PhommasoneVilada ChansamouthSue J. LeePaul N. NewtonStuart D. BlacksellMahosot HospitalMahidol University2018-10-192018-10-192013-05-01American Journal of Tropical Medicine and Hygiene. Vol.88, No.5 (2013), 932-936000296372-s2.0-84877115468https://repository.li.mahidol.ac.th/handle/20.500.14594/31924Inter- and intra-observer variation was examined among six microscopists who read 50 scrub typhus (ST) and murine typhus (MT) indirect immunofluorescence assay (IFA) immunoglobulinM(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); k-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. Copyright © 2013 by The American Society of Tropical Medicine and Hygiene.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.4269/ajtmh.12-0325