Context

Evolution of polymerase chain reaction testing for infectious pathogens has occurred concurrent with a focus on value-based medicine.

Objective

To determine if implementation of the FilmArray rapid respiratory panel (BioFire Diagnostics, Salt Lake City, Utah) (hereafter RRP), with a shorter time to the test result and expanded panel, results in different outcomes for children admitted to the hospital with an acute respiratory tract illness.

Design

Patient outcomes were compared before implementation of the RRP (November 1, 2011, to January 31, 2012) versus after implementation of the RRP (November 1, 2012, to January 31, 2013). The study included inpatients 3 months or older with an acute respiratory tract illness, most admitted through the emergency department. Testing before RRP implementation used batched polymerase chain reaction analysis for respiratory syncytial virus and influenza A and B, with additional testing for parainfluenza 1 through 3 in approximately 11% of patients and for human metapneumovirus in less than 1% of patients. The RRP tested for respiratory syncytial virus, influenza A and B, parainfluenza 1 through 4, human metapneumovirus, adenovirus, rhinovirus/enterovirus, and coronavirus NL62.

Results

The pre-RRP group had 365 patients, and the post-RRP group had 771 patients. After RRP implementation, the mean time to the test result was shorter (383 minutes versus 1119 minutes, P < .001), and the percentage of patients with a result in the emergency department was greater (51.6% versus 13.4%, P < .001). There was no difference in whether antibiotics were prescribed, but the duration of antibiotic use was shorter after RRP implementation (P = .003) and was dependent on receiving test results within 4 hours. If the test result was positive, the inpatient length of stay (P = .03) and the time in isolation (P = .03) were decreased after RRP implementation compared with before RRP implementation.

Conclusions

The RRP decreases the duration of antibiotic use, the length of inpatient stay, and the time in isolation.

The Institute of Medicine1  has identified the need to develop a systems approach to health care delivery, to be a “continuously learning healthcare system.” Having real-time access to knowledge provides the opportunity to deliver the best available evidence to guide clinical decisions. Outcomes research has been heralded as a necessary base on which to provide the best decision making. Laboratory medicine is, perhaps, the most analytical of the medical specialties, with a strong focus on technology and result reporting to provide data for clinical decision making. The type of testing offered by a laboratory must be taken in the context of patient outcomes and not as a sole reflection of the aspects of the test system.

Ramers et al2  were among the first to identify the impact of a laboratory polymerase chain reaction (PCR) test on patient outcomes. They evaluated patient outcomes among children hospitalized at Children's Hospital of San Diego (San Diego, California) who had an enterovirus PCR test on cerebrospinal fluid performed at their hospital during a single calendar year. The study compared outcomes between patients who were enterovirus PCR positive and those who were enterovirus PCR negative. Fifty percent of the patients had enterovirus identified from the cerebrospinal fluid, and 70% had results available before discharge. Patients having a positive enterovirus PCR result before discharge had fewer ancillary tests (26% versus 72%) compared with patients having a negative enterovirus PCR result. Those with a positive enterovirus result also received intravenous antibiotics for less time (2.0 versus 3.5 days) and had shorter hospital stays (42 versus 71.5 hours).

COMMENT

The model for health care reimbursement in the United States is changing, with increased focus on a value-based delivery model rather than a volume-based model.8  The Institute of Medicine1  made 10 recommendations to design a path toward continuously learning health care in America, identifying essentials to become an environment focused on efficient, patient-centered care. Our retrospective study was designed to ask whether implementation of a new test for respiratory pathogens, which expands the number of viruses detected and decreases the length of time to the test result, has an impact on patient outcomes. Our study demonstrated that implementation of the RRP impacts outcomes for patients with a positive test result. Specifically, patients with viral pathogens detected by the RRP had earlier discontinuation of antibiotics, decreased LOS, and reduced time in isolation compared with patients tested the prior year with a viral panel run once a day and reporting fewer pathogens.

Hersh et al9  reported antibiotic use in 70% of children seen in pediatricians' offices with an upper respiratory tract infection and recommended that guidelines be developed to promote the judicious use of antibiotics based on accurate diagnosis. Our study showed that identifying viral pathogens within 4 hours of receipt of the sample in the laboratory decreases the duration of antibiotic use in children hospitalized for an acute respiratory tract illness. A decrease in the duration of antibiotic use was not identified in the group of infants and children who received their test results after 6 hours, indicating that in our population it was necessary for a rapid test result for the physician to act on the result in a measurable way. During the study years, there was no protocol directing antibiotic use in infants and children 3 months or older with an acute respiratory tract illness, so the data reflect the value of the rapid result, with an expanded panel of pathogens, in a setting without a defined protocol. It is unclear if adoption of a standardized treatment protocol would strengthen the association of the findings in the study with a rapid result.

Inpatient LOS was favorably impacted after RRP implementation compared with before RRP implementation, but this difference was seen only when comparing patients with a positive test result. Patients with a negative result had no difference in the LOS, while patients with a positive result were discharged about 6 hours earlier when using the RRP. The reason for this is not clear. One possibility is that, because a viral pathogen was identified in a shorter amount of time after RRP implementation, the caregivers were more comfortable discharging patients with a specific diagnosis based on identification of a viral pathogen compared with patients without a virus identified. Another possibility relates to the difference in influenza pathogens. The year before implementation of the RRP, there were no children with influenza in our study. In the group of excluded patients, only 2 had influenza A and none had influenza B. This was due to an extensive immunization campaign in the Atlanta area following pandemic flu the previous year. The year the RRP was instituted, influenza A and B comprised approximately 17% of the positive results. It is possible that these represented the children discharged earlier following treatment for influenza. We tried to address the impact the difference in cases with influenza had by performing the same analysis with removal of the patients who were positive for influenza. All results were the same as in the entire group, with the exception that statistical significance was not achieved for the LOS and the time in isolation, although both trended downward in the post-RRP group.

The length of time in isolation was also different among patients with a positive result in the pre-RRP group versus the post-RRP group. It was outside of the scope of this study to identify the type of isolation and, therefore, the impact on the patient outcomes. One other difference in the groups before and after RRP implementation was the length of time in the ED, but this difference occurred regardless of whether the test result was positive or negative. The post-RRP group had a mean increase in the length of time in the ED. It is possible that clinicians were waiting for the result before admission to the hospital. It is equally possible that the patient volumes after RRP implementation were sufficiently higher than in the previous year, resulting in longer wait times in the ED before admission.

Because our study was retrospective, it is an evaluation of how implementation of a test with improved turnaround and broader diagnostic capacity affects patient care. Several limitations exist. The first is the number of patients excluded from the analysis. We chose to specifically limit the study population to children with an acute respiratory tract illness admitted to the hospital who were not on a predefined protocol. Because antibiotics are routinely administered to infants younger than 3 months with symptoms of acute respiratory tract infections and because those with significant comorbidities were outliers, they were excluded from the analysis. Owing to the patient population seen in our ED, this resulted in a large number of exclusions. However, these exclusions, which were made by assessment of diagnosis codes and focused medical record review, allowed as homogeneous a population as possible to assess the impact of a change in testing. In addition, the test was performed in the laboratory at times when staffing was available, which resulted in variability in the time to the test result and the ability to assess whether there was any difference in patient care based on the time to a test result. However, these variables afforded the opportunity for assessment of impact related to a change in test method.

In summary, the RRP impacted patient care, resulting in less antibiotic use and shorter time in the hospital following admission. Further refinement to include standardized testing 24 hours a day, 7 days a week, to ensure less than a 2-hour turnaround time and the development of practice guidelines based on the results will be next steps to ensure that this test is used to its fullest potential.

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Author notes

Dr Rogers serves on an advisory board for BioFire Diagnostics FilmArray. The Children's Healthcare of Atlanta microbiology laboratory, under the direction of Drs Jerris and Rogers, has provided samples for testing for the FilmArray gastrointestinal panel and received support from BioFire Diagnostics for a work-motion study. The other authors have no relevant financial interest in the products or companies described in this article.