An Investigation to Improve the Effectiveness of the Use of Real-time Multiplex PCR Testing for Viral Respiratory Infections

Background: Multiplex PCR tests are increasingly used to accurately and rapidly diagnose infectious diseases, including viral respiratory infections (VRI). These tests can assist in addressing clinical challenges such as infection control, antimicrobial stewardship and bed pressures. Optimal use of these tests depends on streamlining all stages of the diagnostic pathway, from sample collection to results reporting. However, often new tests are simply introduced into existing diagnostic pathways that are not designed to provide full advantage from these new, expensive tests.

Objective: To investigate the current use of multiplex PCR testing for VRI and to develop a toolkit to improve practice throughout whole diagnostic pathway.

Methods: VRI testing by PCR was introduced on a 24/7 basis at Birmingham Children’s Hospital (BCH) in autumn 2015. Retrospective review of VRI testing on 3 priority wards (PICU, Paediatric Assessment Unit, Haematology/Oncology) during the 2015-2016 winter. We then undertook a questionnaire survey of clinical staff to determine their understanding and experiences of the diagnostic pathway in autumn 2016.

Results: The 85 tests reviewed took on average twelve hours and seven minutes from sample taken to result availability. Delays were identified during specimen transport to the laboratories, but particularly during laboratory handling. 36/85 samples gave negative results; RSV and rhinoviruses were the commonest viruses detected (16 cases of each). Ward questionnaires indicated that staff considered that infection control isolation management the main reason for testing; the majority of respondents also believed that antibiotic treatment would be influenced in at least 25% of cases.

Conclusion: The testing protocol was inefficient and overly complex; a diagnostic test that took one hour to perform was taking 12 hours to generate results. Opportunities for better clinical management were consequently missed. A redesign of the entire diagnostic pathway is now underway.