title: Probability of a false-negative HIV antibody test result during the window period: a tool for pre- and post-test counselling.
abstract: Failure to understand the risk of false-negative HIV test results during the window period results in anxiety. Patients typically want accurate test results as soon as possible while clinicians prefer to wait until the probability of a false-negative is virtually nil. This review summarizes the median window periods for third-generation antibody and fourth-generation HIV tests and provides the probability of a false-negative result for various days post-exposure. Data were extracted from published seroconversion panels. A 10-day eclipse period was used to estimate days from infection to first detection of HIV RNA. Median (interquartile range) days to seroconversion were calculated and probabilities of a false-negative result at various time periods post-exposure are reported. The median (interquartile range) window period for third-generation tests was 22 days (19-25) and 18 days (16-24) for fourth-generation tests. The probability of a false-negative result is 0.01 at 80 days' post-exposure for third-generation tests and at 42 days for fourth-generation tests. The table of probabilities of falsely-negative HIV test results may be useful during pre- and post-test HIV counselling to inform co-decision making regarding the ideal time to test for HIV.
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC, Canada School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada Darlene.taylor@bccd.ca.
authors.forename: Darlene
authors.initials: D
authors.lastname: Taylor
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC, Canada.
authors.forename: Monica
authors.initials: M
authors.lastname: Durigon
authors.affiliation: Alberta Health Services, Edmonton, AB, Canada.
authors.forename: Heather
authors.initials: H
authors.lastname: Davis
authors.affiliation: Public Health Agency of Canada, Ottawa, ON, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Archibald
authors.affiliation: School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Konrad
authors.affiliation: School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Coombs
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC, Canada School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Gilbert
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC, Canada BCCDC Public Health Microbiology and Reference Laboratory, Vancouver, BC, Canada.
authors.forename: Darrel
authors.initials: D
authors.lastname: Cook
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC, Canada BCCDC Public Health Microbiology and Reference Laboratory, Vancouver, BC, Canada Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Mel
authors.initials: M
authors.lastname: Krajden
authors.affiliation: Alberta Health Services, Edmonton, AB, Canada.
authors.forename: Tom
authors.initials: T
authors.lastname: Wong
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC, Canada Family Practice, University of British Columiba, Vancouver, BC, Canada.
authors.forename: Gina
authors.initials: G
authors.lastname: Ogilvie
mesh_terms: D015492:AIDS Serodiagnosis; D003376:Counseling / Q000379:methods*; D005188:False Negative Reactions; D005260:Female; D015483:HIV Antibodies / Q000097:blood* / Q000276:immunology; D006679:HIV Seropositivity / Q000175:diagnosis*; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000097:blood; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D015483:HIV Antibodies; D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic
keywords: AIDS; HIV; HIV assays; diagnosis; eclipse period; false-negative; seroconversion; testing; window period