Diagnostic Testing for Influenza and RSV in Pediatric Patients

Recommended Diagnostic Tests

The American Academy of Pediatrics recommends using rapid molecular assays (nucleic acid amplification tests) as the first-line diagnostic test for both influenza and RSV in pediatric patients, due to their high sensitivity (86-100%) and specificity (>95%) 1, 2, 3
The Centers for Disease Control and Prevention suggest obtaining a nasopharyngeal swab or nasopharyngeal aspirate for both influenza and RSV testing, as these specimen types provide optimal sensitivity 2, 4, 5
Multiplex molecular assays can simultaneously detect influenza A, B, RSV, and other respiratory pathogens (adenovirus, rhinovirus, parainfluenza 1-3) in 1-2 hours with high sensitivity and specificity 1, 3

The Infectious Diseases Society of America recommends collecting respiratory specimens as close to illness onset as possible, ideally within the first 48 hours when viral shedding is highest and test sensitivity is optimal 1, 6
The American Academy of Pediatrics suggests that nasopharyngeal aspirate or washing is the optimal specimen type, followed by nasopharyngeal swab, and then throat swab combined with nasal swab if nasopharyngeal collection is not feasible 2, 4, 5

The Society for Healthcare Epidemiology of America recommends complete blood count with differential, urea, creatinine, and electrolytes, and liver enzymes for hospitalized patients with influenza or RSV 8, 4
The Pediatric Infectious Diseases Society suggests pulse oximetry and chest radiograph only for children who are hypoxic or have severe illness 8, 4

The American Academy of Pediatrics advises against relying on negative rapid antigen tests to exclude influenza or RSV, due to their low sensitivity (10-70%) 1, 4, 5
The Centers for Disease Control and Prevention recommend against delaying antiviral treatment while awaiting test results in high-risk patients 3, 7