Clinical implications of rapid ePlex® Respiratory Pathogen Panel testing compared to laboratory-developed real-time PCR

Rapid diagnosis of respiratory infections is of great importance for adequate isolation and treatment. Due to the batch-wise testing, laboratory-developed real-time polymerase chain reaction (PCR) assays (LDT) often result in a time to result of one day. Here, LDT was compared with rapid ePlex® Respiratory Pathogen (RP) Panel testing of GenMark Diagnostics (Carlsbad, CA, USA) with regard to time to result, installed isolation precautions, and antibacterial/antiviral treatment. Between January and March 2017, 68 specimens of 64 patients suspected of an acute respiratory infection were tested with LDT and the ePlex® RP panel. The time to result was calculated as the time between sample reception and result reporting. Information regarding isolation and antibacterial/antiviral treatment was obtained from the patient records. Thirty specimens tested LDT positive (47%) and 29 ePlex® RP panel positive (45%). The median time to result was 27.1 h (range 6.5–96.6) for LDT versus 3.4 h (range 1.5–23.6) for the RP panel, p-value < 0.001. In 14 out of 30 patients, isolation was discontinued based on the ePlex® RP panel results, saving 21 isolation days. ePlex® RP panel test results were available approximately one day ahead of the LDT results in the 19 patients receiving antiviral/antibacterial treatment. In addition, two bacterial pathogens, not requested by the physician, were detected using the RP panel. Analysis of respiratory infections with the ePlex® RP panel resulted in a significant decrease in time to result, enabling a reduction in isolation days in half of the patients. Furthermore, syndromic RP panel testing increased the identification of causative pathogens.