Study designs of evaluations included in the review
Clinical studies assessing diagnostic performance were eligible for inclusion. Case series and studies with ambiguous inclusion criteria were excluded from the review. It appears that the included studies were diagnostic cohort studies.
Specific interventions included in the review
Studies of testing for serum procalcitonin were eligible for the review. The cut-off level used in the included studies ranged from 0.4 to 2.0 ng/mL, a value of 0.4 or 0.5 ng/mL being most common.
Participants included in the review
Eligible participants were out-patients with suspected infection studied either in the ED or on admission to hospital. Studies of adult, paediatric and mixed populations were eligible. The prevalence of infection in the included studies ranged from 4.2 to 53.7%, and patients were either self-referred or physician referred.
Outcomes assessed in the review
Studies had to report sufficient data to enable calculation of the sensitivity, specificity and diagnostic odds ratio (OR).
How were decisions on the relevance of primary studies made?
Two reviewers independently selected studies for the review. Any disagreements were referred to a third reviewer and consensus was reached among all three reviewers.