2017 Article - "Performance evaluation of Direct Fluorescent Antibody, Focus Diagnostics SimplexaTM Flu A/B and RSV and Multi-parameter Customized Respiratory Taqman® Array Card in Immunocompromised Patients" (limited access)
Summary: Molecular assays for diagnosis of Flu A, Flu B, and RSV with short turnaround time (TAT) are of considerable clinical importance. In addition, rapid and accurate diagnosis of a large panel of viral and atypical pathogens can be crucial in immunocompromised patients. The objective of the study was to evaluate the performance of the Simplexa™ Direct assay system in comparison with direct fluorescent antibody (DFA) and customized Taqman® Array Card (TAC) testing for RSV, Flu A, and Flu B in immunocompromised patients. FTD Flu/HRSV was used as golden standard reference method for verification testing. Secondly, they evaluate different algorithms for the detection of respiratory pathogens in terms of cost, turn-around-time (TAT) and diagnostic yield. They collected 125 nasopharyngeal swabs (NTS) and 25 BAL samples from symptomatic immunocompromised patients. The overall sensitivity was significantly lower for DFA testing than for the two molecular methods (p<0.05). Performance characteristics of Simplexa™ testing were not significantly different compared to TAC testing (p>0.1). For BAL samples only, the sensitivity and specificity of the Simplexa™ assay was 100%. In total, 6.7%, 16% and 18% of samples were positive for Flu A, Flu B or RSV by DFA, Simplexa™ and TAC testing respectively. When considering not only these pathogens but all results for TAC, the method identified 93 samples with one or more respiratory pathogens (62%). A co-infection rate of 15.3% was found by TAC. The estimated costs and TAT were 8.2€ and 2 hours for DFA, 31.8€ and 1.5 hours for Simplexa™ and 55€ and 3 hours for TAC testing. Taken all this together diagnostic using FTD kits, especially in lyophilized formulation, is extremely time and cost saving!
Kit used: FTD FLU/HRSV