Impact of a Multiplex Respiratory PCR Test on Outcomes for Patients Presenting With Respiratory Illness in the Urgent Care Setting: A Hybrid-Effectiveness Quasi-Experimental Trial

Antimicrobial resistance (AMR) is a critical public health challenge and a significant global burden. In the United States, most antibiotics are prescribed in outpatient settings, with suspicion or confirmation of a respiratory infection serving as a primary driver of unnecessary antibiotic use. This use is deemed inappropriate in approximately 30% of cases. This estimate differs based on setting and patient population. For example, a study assessing antibiotic use in a Veterans Affairs (VA) hospital demonstrated that 64.2% of patients received unnecessary antibiotics, with diagnoses such as bronchitis or nonspecific upper respiratory infections being the most likely to result in antibiotic use. Importantly, antibiotic overuse is not without consequences, as it is associated with adverse events that frequently lead to emergency department (ED) visits. Regardless of setting, acute respiratory conditions, such as acute bronchitis and rhinosinusitis are associated with the highest rates of inappropriate antibiotic prescribing. In cases of pharyngitis, similar trends have been observed. A 2020 study revealed that while Group A streptococcus (GAS) pharyngitis prevalence is 20-30% in children and 5-15% in adults, antibiotics were prescribed in 57% of cases across these groups. Notably, 50% of patients received antibiotics without prior GAS testing , even though laboratory testing is linked to more appropriate prescribing. In a pediatric study, unnecessary antibiotic prescribing occurred in 58% of outpatient visits for bronchitis or bronchiolitis, with diagnostic uncertainty identified as a key factor driving inappropriate use.

The role of multiplex rapid diagnostic tests (mRDTs) in the inpatient setting has been the focus of many studies. Its role on the outpatient care setting remains less studied. In outpatient settings, prescribing behaviors are influenced by factors such as the lack of an established patient-provider relationship, time constraints, patient satisfaction, and medicolegal considerations. Early evidence from studies implementing mRDTs suggests that molecular respiratory rapid diagnostic tests have the potential to positively impact patient care. In ED settings, studies have demonstrated benefits such as decreased test turnaround times (TAT), reduced lengths of stay , and more appropriate antiviral use. However, the impact on antibiotic use and ED length of stay remains mixed, with clinical decision-making and contextual factors playing crucial roles.

The Centers for Disease Control and Prevention (CDC) provides core elements for outpatient antibiotic stewardship programs (ASP), and studies performed in outpatient settings that leverage elements of these recommendations within multifactorial interventions have shown promise in improving stewardship outcomes. On study demonstrated that clinician education combined with audit and feedback improved adherence to prescribing guidelines for bacterial acute respiratory tract infections. Similarly, another study highlighted the effectiveness of a physician behavior change strategy paired with parental education in reducing antibiotic use. More recently, a new study has demonstrated that a multifaceted stewardship approach-including education for both providers and patients, electronic health record tools, benchmarking, and media campaigns-led to reduced antibiotic prescribing for respiratory infections in urgent care settings.

Performance metrics, such as those from the Healthcare Effectiveness Data and Information Set (HEDIS), play a vital role in evaluating antibiotic stewardship efforts. HEDIS measures, used by over 90% of U.S. health plans, help identify performance gaps. Analysis of 2008-2012 HEDIS data that described antibiotic prescribing for acute bronchitis demonstrated poor performance across insurance plans, with antibiotics prescribed in 80% of adult cases. Recently, a newly validated HEDIS measure has been introduced to assess antibiotic use for respiratory conditions, emphasizing "measurement" (i.e., utilization, improvement) as a core element of outpatient stewardship. This measure has broad support among antibiotic stewardship programs and health plan stakeholders and is used to evaluate care quality for over 200 million individuals.

Implementation science is a relatively recent arm of clinical research that aims to increase the adoption and sustainability of evidence-based interventions. Years of research has demonstrated that innovation uptake relies on contextual factors in addition to effectiveness. To fully understand the impact of diagnostic innovation on clinical outcomes, it is important to consider these elements together.

The BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel is a multiplexed polymerase chain reaction (PCR) test intended for use with the BIOFIRE® SPOTFIRE® System for the simultaneous, qualitative detection and identification of multiple respiratory viral and bacterial nucleic acids in nasopharyngeal swab (NPS) specimens obtained from individuals with signs and symptoms of respiratory tract infection, including COVID-19; (Respiratory menu) or in throat swab (TS) specimens from individuals with signs and symptoms of pharyngitis (Sore Throat menu). Time from test initiation to result is approximately 15 minutes.

The SPOTFIRE R/ST Panel, designed for use with the SPOTFIRE System, is a PCR based sample-to-answer diagnostic test that simultaneously identifies nucleic acids from 15 different bacterial and viral organisms from nasopharyngeal swab (NPS) specimens, or 14 different bacterial and viral organisms from TS specimens, in transport media collected from individuals with signs and symptoms of respiratory infection or pharyngitis, respectively. The SPOTFIRE R/ST Panel uses a single instrument protocol with different reporting of analytes for the two sample types. Sample type is selected at the time of testing and the system's software controls the analyte reporting based on the selected sample type.

Nucleic acids from the viral and bacterial organisms identified by this test are generally detectable in NPS/TS specimens during the acute phase of infection. The detection and identification of specific viral and bacterial nucleic acids from individuals exhibiting signs and symptoms of respiratory infection and/or pharyngitis are indicative of the presence of the identified microorganism and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.

Negative results in the setting of a respiratory illness and/or pharyngitis may be due to infection with pathogens that are not detected by this test, or a respiratory tract infection that may not be detected by an NPS or TS specimen. Positive results do not rule out the possibility of coinfection with other organisms. The agent(s) detected by the SPOTFIRE R/ST Panel may not be the definite cause of disease.

At the clinician's discretion, additional laboratory testing (e.g., bacterial and viral culture, immunofluorescence, and radiography) may be performed when evaluating a patient with possible respiratory tract infection and/or pharyngitis.

The SPOTFIRE R/ST Panel is intended for use by non-laboratory trained healthcare professionals in a facility holding a CLIA Certificate of Waiver (in the United States) or it may also be used by trained medical and laboratory professionals in a laboratory setting or under the supervision of a trained laboratory professional.