Implementation of FilmArray Respiratory Viral Panel
Implementation of FilmArray Respiratory Viral Panel
Respiratory virus testing with FilmArray was initiated on December 14, 2011. During the 4-month period ending April 19, 2012, a total of 2,537 specimens were tested. Seventy-one percent of the samples were from the ED or urgent care. The daily testing volume varied from 3 to 44 Figure 1. The average daily volume for the first 2 months and second 2 months were 15 and 25, respectively. Because the FilmArray instrument is designed for single-specimen throughput and requires 65 minutes of instrument time, we purchased 3 instruments that could run simultaneously 24 hours a day. The average and median TAT was 1.6 and 1.4 hours, respectively, with 82% completed in less than 2 hours and 95% in less than 3 hours Table 1. Before this molecular test was available, we sent respiratory viral testing to an on-site reference laboratory for DFA. DFA testing involved multiple handoff steps in our laboratory and specimen transport to the reference laboratory. DFA specimens were run in batches 3 or 4 times per day depending on the volume during respiratory virus season. The testing time was approximately 3 hours. During the same period 1 year previously, 1,399 DFAs for respiratory viruses were performed. The average and median TAT for DFA was 7 and 6.5 hours, respectively, with 2% completed in less than 3 hours (Table 1). The test volume of respiratory virus during the study period was almost doubled compared with the same period last year. During the study period, the instrument failed 4 times. The rate of failed testing, which included quality control failures, insufficient vacuum in the pouch, and pouch leaking, was 1.3%. The TAT was significantly longer when instruments or reagent pouches failed.
(Enlarge Image)
Figure 1.
Daily volume of FilmArray respiratory viral testing was tallied during the period from December 14, 2011, to April 19, 2012.
During the study period, 63% of all samples tested positive for viral agents. Rhinovirus/enterovirus and RSV were detected in 20% and 18% of total samples, respectively. The other viral agents detected were influenza B (10%), human metapneumovirus (7%), influenza A (6%–2% H12009, 4% H3), coronavirus (HKU1 and NL63) (6%), adenovirus (2%), and parainfluenza virus type 1–4 (2%). DFA does not detect rhinovirus and coronavirus. Thus, in an additional 660 (26%) of 2,537 specimens, FilmArray detected viruses that would not have been detected with DFA.
Current guidelines for treating patients with influenza A or B infection with oseltamivir indicate that the medication should be given within 48 hours of symptom onset to be most effective. In general, children with respiratory symptoms may not seek or be brought to medical attention immediately. A delay in laboratory testing may further prolong the interval between symptom onset and the administration of medication. For treatment benefits, we specifically followed patients (n = 97) who tested positive for influenza A or influenza B admitted to the ED during March 2012. The mean and median length of stay in the ED during the study period was 3.1 and 2.8 hours, respectively. In these 97 patients, respiratory viral results provided by FilmArray were available for 44 patients (45%) before they were discharged from the ED. In 50 patients (52%), positive results were called within 3 hours after discharge. The remaining 3 patients (3%) were notified of the results in more than 3 hours. Of the 97 patients, 22 patients (23%) were treated with oseltamivir in the ED, and 30 patients (31%) were given the prescription while they were in the ED. The prescription was called in to another 27 patients (28%) within 3 hours after discharge from the ED. The remaining 18 (19%) patients received no prescription for oseltamivir. Overall, 79 patients (81%) with influenza virus 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. Among the 18 patients who did not receive prescriptions, 6 reported having symptoms for more than 48 hours before the ED visit, 4 patients showed improvement of symptoms according to parents, 4 had a follow-up appointment, 2 received physicians' decisions not to treat, and no information was available for 2 patients.
The daily tally of all positive results during the respiratory virus season clearly demonstrated the epidemiology of the multiple respiratory viral agents present in symptomatic children receiving care at our institution Figure 2 and contributed to both hospital-wide as well as community-wide public health information. Unusually, influenza A and B did not emerge until later in the season at the end of February and peaked in April. Before the emergence of influenza viruses, RSV was the major infectious agent, with a peak noted in mid-February. We also found that 1 patient who received live attenuated influenza vaccine less than 7 days before testing was positive for both influenza A and B; in retrospect, we would not recommend viral testing in patients recently immunized with live vaccine.
(Enlarge Image)
Figure 2.
Weekly respiratory samples detected as positive for influenza A H1 2009, influenza H3, influenza B, respiratory syncytial virus (RSV), or rhinovirus/enterovirus.
Results
Respiratory virus testing with FilmArray was initiated on December 14, 2011. During the 4-month period ending April 19, 2012, a total of 2,537 specimens were tested. Seventy-one percent of the samples were from the ED or urgent care. The daily testing volume varied from 3 to 44 Figure 1. The average daily volume for the first 2 months and second 2 months were 15 and 25, respectively. Because the FilmArray instrument is designed for single-specimen throughput and requires 65 minutes of instrument time, we purchased 3 instruments that could run simultaneously 24 hours a day. The average and median TAT was 1.6 and 1.4 hours, respectively, with 82% completed in less than 2 hours and 95% in less than 3 hours Table 1. Before this molecular test was available, we sent respiratory viral testing to an on-site reference laboratory for DFA. DFA testing involved multiple handoff steps in our laboratory and specimen transport to the reference laboratory. DFA specimens were run in batches 3 or 4 times per day depending on the volume during respiratory virus season. The testing time was approximately 3 hours. During the same period 1 year previously, 1,399 DFAs for respiratory viruses were performed. The average and median TAT for DFA was 7 and 6.5 hours, respectively, with 2% completed in less than 3 hours (Table 1). The test volume of respiratory virus during the study period was almost doubled compared with the same period last year. During the study period, the instrument failed 4 times. The rate of failed testing, which included quality control failures, insufficient vacuum in the pouch, and pouch leaking, was 1.3%. The TAT was significantly longer when instruments or reagent pouches failed.
(Enlarge Image)
Figure 1.
Daily volume of FilmArray respiratory viral testing was tallied during the period from December 14, 2011, to April 19, 2012.
During the study period, 63% of all samples tested positive for viral agents. Rhinovirus/enterovirus and RSV were detected in 20% and 18% of total samples, respectively. The other viral agents detected were influenza B (10%), human metapneumovirus (7%), influenza A (6%–2% H12009, 4% H3), coronavirus (HKU1 and NL63) (6%), adenovirus (2%), and parainfluenza virus type 1–4 (2%). DFA does not detect rhinovirus and coronavirus. Thus, in an additional 660 (26%) of 2,537 specimens, FilmArray detected viruses that would not have been detected with DFA.
Current guidelines for treating patients with influenza A or B infection with oseltamivir indicate that the medication should be given within 48 hours of symptom onset to be most effective. In general, children with respiratory symptoms may not seek or be brought to medical attention immediately. A delay in laboratory testing may further prolong the interval between symptom onset and the administration of medication. For treatment benefits, we specifically followed patients (n = 97) who tested positive for influenza A or influenza B admitted to the ED during March 2012. The mean and median length of stay in the ED during the study period was 3.1 and 2.8 hours, respectively. In these 97 patients, respiratory viral results provided by FilmArray were available for 44 patients (45%) before they were discharged from the ED. In 50 patients (52%), positive results were called within 3 hours after discharge. The remaining 3 patients (3%) were notified of the results in more than 3 hours. Of the 97 patients, 22 patients (23%) were treated with oseltamivir in the ED, and 30 patients (31%) were given the prescription while they were in the ED. The prescription was called in to another 27 patients (28%) within 3 hours after discharge from the ED. The remaining 18 (19%) patients received no prescription for oseltamivir. Overall, 79 patients (81%) with influenza virus 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. Among the 18 patients who did not receive prescriptions, 6 reported having symptoms for more than 48 hours before the ED visit, 4 patients showed improvement of symptoms according to parents, 4 had a follow-up appointment, 2 received physicians' decisions not to treat, and no information was available for 2 patients.
The daily tally of all positive results during the respiratory virus season clearly demonstrated the epidemiology of the multiple respiratory viral agents present in symptomatic children receiving care at our institution Figure 2 and contributed to both hospital-wide as well as community-wide public health information. Unusually, influenza A and B did not emerge until later in the season at the end of February and peaked in April. Before the emergence of influenza viruses, RSV was the major infectious agent, with a peak noted in mid-February. We also found that 1 patient who received live attenuated influenza vaccine less than 7 days before testing was positive for both influenza A and B; in retrospect, we would not recommend viral testing in patients recently immunized with live vaccine.
(Enlarge Image)
Figure 2.
Weekly respiratory samples detected as positive for influenza A H1 2009, influenza H3, influenza B, respiratory syncytial virus (RSV), or rhinovirus/enterovirus.
