Comparison of Passive Hemagglutination and Indirect Immunofluorescence Assay for the Diagnosis of Scrub typhus / 감염과화학요법

ABSTRACT

The gold standard for the serologic detection of scrub typhus is the indirect immunofluorescence assay (IFA), however the passive hemagglutination assay (PHA) is commonly used method in Korea because of its availability, easy handling. We compared the sensitivity of PHA and IFA to compare their effectiveness in diagnosing scrub typhus. Out of 35 patients who were eventually diagnosed of scrub typhus by positive IFA, 19 patients (54%) were also tested positive for PHA during the acute phase (titer=180). Whereas 30 patients (85%) were positive in IFA during the acute phase. During the recovery phase 30 (85%) patients were positive in PHA, whereas all patients were found to be positive in IFA. Patients with 4-fold or greater rise of antibody were 12 (34.3%) in PHA, and 19 (54.3%) in IFA. We note that IFA has better sensitivity over PHA in detecting scrub typhus.