Study designs of evaluations included in the review
Independent cohort studies and randomised controlled trials RCTs) were eligible for inclusion. All included studies were cohort studies.
Specific interventions included in the review
Studies of HPE for the diagnosis of influenza A and/or influenza B were eligible for inclusion. The individual included studies examined a total of 59 different individual or combinations of characteristics, such as the presence of abdominal pain, rigour or chills (full details were reported). The studies were conducted in community or out-patient settings, mostly in primary care and during an influenza epidemic.
Reference standard test against which the new test was compared
Studies that reported a laboratory test as the reference standard were eligible for inclusion. The specific tests used in the included studies were enzyme-linked immunosorbent assay, four-fold rise in influenza titres, fluorescent monoclonal antibodies, culture or positive serology, and direct immunofluorescence.
Participants included in the review
The review did not specify any inclusion criteria for the participants. The majority of participants in the included studies were patients with suspected influenza; other studies included patients with respiratory infection. The studies included both adults and children. The mean age of the participants ranged from 33.2 to 76 years; in one study the mean age in children was 5 years.
Outcomes assessed in the review
The studies had to provide sufficient information to calculate the sensitivity and specificity to be eligible for inclusion.
How were decisions on the relevance of primary studies made?
Two reviewers screened the identified papers independently. Any disagreements were resolved by consensus discussion, or by referral to a third reviewer.