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Abstract and Introduction
Abstract
The FilmArray respiratory virus panel detects 15 viral agents in respiratory specimens using polymerase chain reaction. We performed FilmArray respiratory viral testing in a core laboratory at a regional children's hospital that provides service 24 hours a day 7 days a week. The average and median turnaround time were 1.6 and 1.4 hours, respectively, in contrast to 7 and 6.5 hours documented 1 year previously at an on-site reference laboratory using a direct fluorescence assay (DFA) that detected 8 viral agents. During the study period, rhinovirus was detected in 20% and coronavirus in 6% of samples using FilmArray; these viruses would not have been detected with DFA. We followed 97 patients with influenza A or influenza B who received care at the emergency department (ED). Overall, 79 patients (81%) were given oseltamivir in a timely manner defined as receiving the drug in the ED, a prescription in the ED, or a prescription within 3 hours of ED discharge. Our results demonstrate that molecular technology can be successfully deployed in a nonspecialty, high-volume, multidisciplinary core laboratory.
Introduction
Acute respiratory infection is a leading cause of outpatient visits and hospitalization in young children, especially in winter and spring. Most of the acute respiratory infections are caused by viral agents, with primary or secondary bacterial infections occurring less frequently. Without definitive diagnosis, patients with viral infection are more likely to receive unnecessary antibacterial agents. Therefore, laboratory tests providing accurate, timely determination of the infectious agents associated with viral respiratory disease are important. A broad array of tests is available to detect viral respiratory agents. Rapid antigen tests are available for individual respiratory viruses such as influenza A, influenza B, and respiratory syncytial virus (RSV). However, these tests have low sensitivity and specificity. Several molecular tests have been developed to detect viral RNA or DNA using the polymerase chain reaction (PCR) method. These tests show high sensitivity and specificity, but most of these molecular tests are technically challenging and time consuming and require experienced, specialized medical technologists. They are usually performed in large medical centers in highly specialized molecular or virology laboratories with limited hours of operation.
FilmArray (Idaho Technologies, Salt Lake City, UT) is a small desktop closed single-piece flow real-time PCR system. This end-to-end molecular system includes automation of nucleic acid extraction, an initial reverse transcription and multiplex PCR, followed by singleplex second-stage PCR reactions for detection of specific viral agents in a single-use cartridge. The respiratory virus panel performed on FilmArray is able to detect 15 viral agents from respiratory specimens. The test requires 5 minutes hands-on time and 65 minutes of instrumentation time. Comparison studies between FilmArray and other molecular tests for respiratory viral agents showed comparable results. As part of our preimplementation planning, we surveyed 10 other clinical laboratories in the United States. Only 1 laboratory performed the test in the general laboratory, with the rest performing the test in the microbiology, virology, or molecular laboratories. We reasoned that a general medical technologist with proper training would be able to perform the test.
To provide 24 hours per day, 7 days per week (24/7) service to our emergency department (ED) and urgent care center, we decided to perform the test in the core laboratory. Our core laboratory is a rapid response facility staffed by approximately 35 full-time equivalent (FTE) employees providing analysis encompassing automated chemistry, hematology, coagulation, urinalysis, blood gas analysis, and selected therapeutic drug monitoring. In addition, individual manual tests such as pregnancy tests, cardiac markers, drug abuse screening, sickle cell screening, occult blood, and heterophil antibodies are also performed in the core laboratory. We do not currently have a 24/7 microbiology laboratory, and during the night shift the core technologists perform culture setup and Gram staining. Our core specimen processing and testing are designed based on lean, single-piece flow principles without batching. Because the core laboratory was already involved in such work flow, the institution of FilmArray should be relatively simple.
In this study we describe the implementation of FilmArray in the core laboratory to provide rapid 24/7 service for respiratory virus diagnosis.
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