Influenza is primarily diagnosed clinically. Based on the presentation of symptoms, clinicians make a diagnosis and provide the appropriate treatment recommendation. If diagnosed within 48 hours of the onset symptoms, treatment may consist of anti-influenza medication along with rest, hydration, and pain relief. The limitation of a clinical diagnosis is that the symptoms of influenza can present very similarly to other common infectious agents including Myocplasma pneumonia, adenovirus, and the virus responsible for the 2020 pandemic – COVID-19. In light of the significant consequences of a missed diagnosis of COVID-19, it may prove worthwhile to delineate the actual viral pathogen.
Tests available to diagnose influenza include a viral culture that takes 3-10 days, polymerase chain reaction that takes 1-8 hours, immunofluorescence assays that take 1-4 hours, rapid molecular assays that take 15-30 minutes, and rapid influenza antigen detection tests that take less than 15 minutes. In an outpatient setting where time is of the essence as it relates to appointment time and initiating treatment to reduce the length of illness, it is prudent to be able to quickly test and quickly receive results.
Influenza is an acute viral illness. It has four subtypes A, B, C, and D with the first three causing disease in humans and Subtype D causing disease in pigs and cattle. Influenza A and B are the most prevalent in the United States during winter months peaking December to February.
These two subtypes cause an epidemic every year whereby 3-11% of the population becomes symptomatic. This highly contagious virus is transmitted through respiratory droplets. Symptoms may include high temperature, cough, muscle pain, fatigue, and sweats. Symptoms can last two or more weeks and in severe cases it can lead to hospitalization or death. Due to the significant antigenic variation in influenza A, it is difficult to develop a vaccination that confers complete protection and thus Flu A is responsible for major pandemics.
The BD Veritor Plus is a CLIA-waived office-based rapid antigen detection testing device. It has the ability to test multiple common upper respiratory infections including Flu A and B, Group A Strep, RSV (respiratory syncytial virus) and SARS-CoV-2 used to detect the coronavirus known as COVID-19. A nasopharyngeal swab is used to collect a specimen. The swab is then placed in the processing tube.
The clinician can decide to use one of two modes – walk away or analyze now. If the “walk away” mode is used, 3 drops from the processing tube are placed on the testing device. After 10 minutes the device is inserted in the BD Veritor and the results are displayed on the screen. If the “analyze now” mode is chosen, 3 drops from the processing tube are placed on the testing device that is immediately inserted into the machine. After 10 minutes the results will be displayed on the screen.
The BD Veritor allows for point of care testing and treatment foregoing a long delay and allowing prompt action. Rapid diagnostic results, wide availability, and ease of testing with devices such as the BD Veritor Plus have proven even more valuable during this time.