Respiratory Pathogen Testing

A large variety of disease-causing microbes, called pathogens, including viruses and bacteria can cause respiratory tract infections. This panel tests for the presence of multiple pathogens from a single respiratory sample. For people with a serious illness or who are at risk of complications from a respiratory infection, Respiratory Pathogen Panel (RPP) testing can aid physicians in determining which pathogen is causing the illness and which medication would be best suited to treat the illness. qPCR pathogen panels provide testing for a greater variety of pathogens which help to provide accurate diagnosis. Accurate diagnosis of the pathogen(s) present leads to appropriate treatment and antibiotic stewardship.

Respiratory tract infections are the most frequent cause of acute illness in developed countries, with an estimated incidence of 500 million non-influenza virus respiratory infections occurring annually in the United States (1, 2). The vast majority of respiratory infections are caused by viruses, the most common of which are rhinoviruses, coronaviruses, influenza viruses, respiratory syncytial virus (RSV), parainfluenza virus (PIV), human metapneumovirus (hMPV), and adenovirus (3). These infections account for a substantial proportion of outpatient medical visits and are associated with an estimated $17.3 billion in direct annual costs, including more than $1.1 billion spent on an estimated 41 million unnecessary antibiotic prescriptions for viral infections (2).

Diagnosis of respiratory infections is based largely on clinical signs and symptoms, since there are a myriad viral etiologies that present with similar clinical features. Techniques that have been used to identify specific viruses include viral culture, direct fluorescent-antibody (DFA) staining, rapid antigen determination tests (RADTs), and pathogen-specific PCR assays. However, each of these methodologies has significant limitations (4): viral culture and DFA staining are labor-intensive and require highly skilled laboratories, and culture results are not available in time to affect patient management. Although they produce results much faster, RADTs are relatively insensitive, and pathogen-specific PCRs can test for only a single viral etiology.

Many of these limitations can be overcome with multiplex respiratory PCR panels, which are increasingly being used in the outpatient setting for patients with upper respiratory infections (URIs).