CDC publishes guidance on testing for flu, COVID-19
Patients presenting with acute respiratory illness should be tested for SARS-CoV-2 with nucleic acid detection or antigen detection assay, as well as flu if the results will change clinical management or infection control decisions, the CDC said.
The CDC recently updated its online guidance about viral testing of patients with acute respiratory illness.
The guidance, which applies when influenza and COVID-19 are both circulating, is categorized by health care setting and was updated on the CDC website on Dec. 6.
For patients who are seen in an outpatient setting and not expected to be hospitalized, the CDC recommends implementing infection prevention and control measures and collecting respiratory specimens for influenza and SARS-CoV-2 testing. Patients should be tested for SARS-CoV-2 with nucleic acid detection or antigen detection assay, especially if they are at high risk for progression to severe COVID-19. Because antigen tests have lower sensitivity, negative results should be confirmed by repeat testing 48 hours later if clinical suspicion for COVID-19 is high.
As for flu symptoms in outpatients, the guidance recommends a rapid influenza nucleic acid detection assay if the results will change clinical management or infection control decisions (e.g. long-term care facility resident returning to a facility or a person of any age returning to a congregate setting).
Guidance for patients expected to be hospitalized recommends the multiplex nucleic acid detection assay for influenza A/B/SARS-CoV-2. Testing for respiratory syncytial virus should be considered in certain high-risk patients (e.g., infants, patients with congenital cardiac disease, chronic lung disease, immunocompromised, elderly), the hospital guidelines say.
Regarding treatment, the guidance recommends supportive care for COVID-19, as well as prescription treatment if a patient is at high risk for progression to severe COVID-19, per NIH guidelines. If a flu test is positive, prescribe influenza antiviral treatment. Empiric antiviral treatment, without test results, can be used in patients who have progressive disease or are at high risk. If healthy low-risk patients are within two days of flu symptom onset, empiric flu antivirals can be prescribed based upon clinical judgment. If it's been more than two days, antiviral treatment of influenza is unlikely to provide significant clinical benefit. Suspected pneumonia should be treated according to relevant society guidelines.
Finally, clinicians should provide patients with isolation and quarantine recommendations for SARS-CoV-2, arrange follow-up for any pending testing results, and recommend appropriate vaccinations.