Clinical evaluation of a multi-parameter customized respiratory TaqMan® array card compared to conventional methods in immunocompromised patients

• Evaluation of customized TaqMan® array card, targeting 34 pathogens simultaneously.
• TAC assay identified virus in significantly more samples.
• Even after exclusion of viruses that could not be detected by conventional testing.
• Immunocompromised patient population with overall positivity rate of 52.4%.
• Viral and total pathogen co-infection rate of 5.6% and 11.8%, respectively.

BackgroundRespiratory viral infections can cause significant morbidity and mortality in immunocompromised patients. Conventional tests routinely available at most institutions are limited by the number of detectable pathogens, by a poor sensitivity and/or a long turnaround time.ObjectivesTo compare the performance of routine conventional testing with direct fluorescent antibody assays and viral culture to a customized TaqMan® array card (TAC) real-time PCR method, targeting 24 viruses, 8 bacteria and 2 fungi simultaneously.Study designWe collected 143 respiratory samples from 120 symptomatic immunocompromised patients. Samples for which conventional and TAC results were discordant underwent further verification testing.ResultsThe TAC assay identified viral pathogens in more samples than did conventional testing (77/143 versus 27/143; McNemar P < 0.0001), even when TAC results for viruses that could not be detected by conventional testing were excluded from analysis (59/143 versus 26/143; P < 0.0001). In addition, the TAC assay identified 18 samples with non-viral pathogens. Verification testing confirmed positive TAC results for 50 out of 55 samples for which conventional testing was negative. Two out of three samples with a positive conventional test but negative TAC result were confirmed positive. A viral and a total pathogen co-infection rate of 5.6% and 11.8% were found, respectively.ConclusionsThe customized TAC assay resulted in a significantly increased identification of respiratory viruses. This study provides a practical real-life assessment of the performance of the TAC assay in a population for whom rapid and accurate diagnosis of viral and atypical pathogens is crucial for appropriate clinical management.