Health Technology Assessment (Oct 2024)
Diagnostic accuracy of point-of-care tests for acute respiratory infection: a systematic review of reviews
Abstract
Background Acute respiratory infections are a common reason for consultation with primary and emergency healthcare services. Identifying individuals with a bacterial infection is crucial to ensure appropriate treatment. However, it is also important to avoid overprescription of antibiotics, to prevent unnecessary side effects and antimicrobial resistance. We conducted a systematic review to summarise evidence on the diagnostic accuracy of symptoms, signs and point-of-care tests to diagnose bacterial respiratory tract infection in adults, and to diagnose two common respiratory viruses, influenza and respiratory syncytial virus. Methods The primary approach was an overview of existing systematic reviews. We conducted literature searches (22 May 2023) to identify systematic reviews of the diagnostic accuracy of point-of-care tests. Where multiple reviews were identified, we selected the most recent and comprehensive review, with the greatest overlap in scope with our review question. Methodological quality was assessed using the Risk of Bias in Systematic Reviews tool. Summary estimates of diagnostic accuracy (sensitivity, specificity or area under the curve) were extracted. Where no systematic review was identified, we searched for primary studies. We extracted sufficient data to construct a 2 × 2 table of diagnostic accuracy, to calculate sensitivity and specificity. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies version 2 tool. Where possible, meta-analyses were conducted. We used GRADE to assess the certainty of the evidence from existing reviews and new analyses. Results We identified 23 reviews which addressed our review question; 6 were selected as the most comprehensive and similar in scope to our review protocol. These systematic reviews considered the following tests for bacterial respiratory infection: individual symptoms and signs; combinations of symptoms and signs (in clinical prediction models); clinical prediction models incorporating C-reactive protein; and biological markers related to infection (including C-reactive protein, procalcitonin and others). We also identified systematic reviews that reported the accuracy of specific tests for influenza and respiratory syncytial virus. No reviews were found that assessed the diagnostic accuracy of white cell count for bacterial respiratory infection, or multiplex tests for influenza and respiratory syncytial virus. We therefore conducted searches for primary studies, and carried out meta-analyses for these index tests. Overall, we found that symptoms and signs have poor diagnostic accuracy for bacterial respiratory infection (sensitivity ranging from 9.6% to 89.1%; specificity ranging from 13.4% to 95%). Accuracy of biomarkers was slightly better, particularly when combinations of biomarkers were used (sensitivity 80–90%, specificity 82–93%). The sensitivity and specificity for influenza or respiratory syncytial virus varied considerably across the different types of tests. Tests involving nucleic acid amplification techniques (either single pathogen or multiplex tests) had the highest diagnostic accuracy for influenza (sensitivity 91–99.8%, specificity 96.8–99.4%). Limitations Most of the evidence was considered low or very low certainty when assessed with GRADE, due to imprecision in effect estimates, the potential for bias and the inclusion of participants outside the scope of this review (children, or people in hospital). Future work Currently evidence is insufficient to support routine use of point-of-care tests in primary and emergency care. Further work must establish whether the introduction of point-of-care tests adds value, or simply increases healthcare costs. Funding This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme as award number NIHR159948. Plain language summary What is the problem? Respiratory infections are a common cause of illness. Currently, healthcare professionals use clinical experience to decide whether an infection is caused by a virus or bacteria, and whether antibiotics are needed. However, this is not always easy to establish. We tried to identify the effectiveness of rapid tests (with results in under 45 minutes) at distinguishing between viral and bacterial respiratory infections. What did we do? We identified and summarised all the existing reviews and studies in this area. We looked at many different tests which aim to distinguish between bacterial and viral causes of respiratory infections. In particular, we assessed: individual symptoms and signs (such as the presence of cough, or a fever) combinations of symptoms and signs (the presence or absence of multiple symptoms) various ‘biomarker’ tests (blood tests for evidence that the body has used its defence mechanisms) We also looked at specific tests for flu and respiratory syncytial virus, which are common causes of viral infection. What did we find? The reviews we found showed symptoms and signs were not able to identify bacterial infections in people accurately. The accuracy of biomarker tests was slightly better, particularly when multiple markers were used. The accuracy of rapid tests for flu and respiratory syncytial virus varied; the most accurate tests were those that detect viral genetic material. We also found studies showing that genetic tests that identify many viruses at once (multiplex tests) were very accurate. However, most of the evidence we identified was not robust. There were concerns about the conduct of some of the studies. In some cases there was uncertainty whether a test was really accurate enough to be useful. Therefore there is still doubt about whether any of these tests will be useful additions to current clinical care.
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