The tests for influenza A and B use nasal or nasopharyngeal swabs. Rapid antigen tests (RIDTs) detect viral proteins and give results in 10–30 minutes but have lower sensitivity. Molecular tests (RT‑PCR/NAAT) detect viral RNA, are more sensitive and specific, and are the gold standard. Testing is most accurate within the first 3–4 days of symptoms.

Influenza A and B are diagnosed by clinical assessment plus laboratory testing of respiratory specimens (nasal, nasopharyngeal or throat swabs). Rapid antigen tests provide quick but less sensitive results; rapid molecular assays and RT‑PCR are more accurate and are the diagnostic standard. Viral culture is rarely used. Testing is recommended for hospitalized, high‑risk, severe cases or during outbreaks to guide care and control.

The PCR test for influenza A and B is a molecular assay that detects viral RNA in respiratory samples, usually nasopharyngeal or throat swabs. Reverse-transcription PCR amplifies and identifies influenza A and B, often as part of multiplex panels, offering high sensitivity and specificity for early diagnosis. Results are typically available within hours to a day, guiding antiviral treatment and infection-control decisions.

Influenza A and B are two types of seasonal flu viruses. Influenza A infects humans and animals, is classified by H and N subtypes, and can cause larger outbreaks or pandemics. Influenza B mainly infects humans, has two main lineages (Victoria and Yamagata), and shows less antigenic variation. Both cause similar respiratory symptoms; vaccines and antivirals help prevent and treat infection.

Reverse transcription polymerase chain reaction (RT‑PCR) on a respiratory specimen (usually a nasopharyngeal swab or aspirate) is the diagnostic gold standard to confirm influenza because of its high sensitivity and specificity. Rapid antigen tests give quick results but have lower sensitivity. Viral culture can also confirm infection but is slower and mainly used for surveillance or special cases.

If a test is positive for influenza B, isolate at home to avoid spreading, rest, hydrate, and use fever/ache relief such as paracetamol or ibuprofen. Antiviral treatment (e.g., oseltamivir) may be recommended, especially for severe cases or high‑risk people—start promptly. Monitor closely and seek urgent care for breathing problems, chest pain, persistent fever, confusion, or worsening symptoms, and follow your healthcare provider’s advice.