title: Is Follow-Up Testing with the FilmArray Gastrointestinal Multiplex PCR Panel Necessary?
abstract: The FilmArray gastrointestinal (GI) panel (BioFire Diagnostics, Salt Lake City, UT) is a simple, sample-to-answer, on-demand, multiplex, nucleic acid amplification test for syndromic diagnosis of infectious gastroenteritis. The aim of this study was to measure the yield of follow-up testing with FilmArray GI panel within 4 weeks of an initial test. Consecutive adult and pediatric patients tested at an academic institution between August 2015 and June 2016 were included in this study. Of 145 follow-up tests in 106 unique patients with an initial negative result, 134 (92.4%) tests and 98 (92.5%) patients remained negative upon follow-up testing. Excluding targets that are not reported at this institution (Clostridium difficile, enteroaggregativeEscherichia coli, enteropathogenicE. coli, and enterotoxigenicE. coli), 137 (94.5%) follow-up tests and 101 (95.3%) patients remained negative. Weekly conversion rates were not significantly different across the 4-week follow-up interval. No epidemiological or clinical factors were significantly associated with a negative to positive conversion. Of 80 follow-up tests in patients with an initial positive result, 43 (53.8%) remained positive for the same target, 34 (42.5%) were negative, and 3 were positive for a different target (3.8%). Follow-up testing with FilmArray GI panel within 4 weeks of a negative result rarely changed the initial result, and the follow-up test reverted to negative less than half the time after an initial positive result. In the absence of clinical or epidemiological evidence for a new infection, follow-up testing should be limited and FilmArray GI panel should not be used as a test of cure.
authors.affiliation: Department of Laboratory Medicine, Ewha Womans University School of Medicine, Seoul, South Korea.|Clinical Microbiology Laboratory, Stanford Health Care, Stanford, California, USA.
authors.forename: Sholhui
authors.initials: S
authors.lastname: Park
authors.affiliation: Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Hitchcock
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.|Clinical Microbiology Laboratory, Stanford Health Care, Stanford, California, USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Gomez
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA nbanaei@stanford.edu.|Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.|Clinical Microbiology Laboratory, Stanford Health Care, Stanford, California, USA.
authors.forename: Niaz
authors.initials: N
authors.lastname: Banaei
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005759:Gastroenteritis / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods* / Q000706:statistics & numerical data*; D060885:Multiplex Polymerase Chain Reaction / Q000379:methods* / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D055815:Young Adult
keywords: FilmArray gastrointestinal; GI PCR; repeat; syndromic