Influenza A is tested by collecting respiratory specimens (nasal or nasopharyngeal swab, throat swab) and using rapid antigen tests or molecular assays. Rapid diagnostic tests give quick but less sensitive results; RT‑PCR and other nucleic acid amplification tests are more accurate and can subtype the virus. Viral culture is used rarely. Testing is most reliable when done early in illness (first few days).

Yes. Over-the-counter at-home rapid tests for influenza A (and B) are available in some regions and use nasal swabs for quick antigen detection. They’re convenient but less sensitive than laboratory PCR; accuracy is highest early in illness. Follow kit instructions carefully. If results are positive, or if symptoms are severe or persistent despite a negative test, contact a healthcare provider for confirmatory testing and treatment.

If you test positive for influenza A, stay home, isolate from others, rest and drink plenty of fluids. Use paracetamol or ibuprofen for fever and pain. Antiviral treatment (e.g., oseltamivir) may be advised—especially if you’re high‑risk or within 48 hours of symptom onset—so contact your clinician. Seek urgent care for severe signs (difficulty breathing, chest pain, confusion, dehydration). Follow hygiene and return to activities once fever‑free for 24 hours.

A routine blood test does not reliably diagnose acute influenza. Diagnosis is made by detecting virus in respiratory samples (nasal/throat swabs) using rapid antigen tests or PCR. Blood can show nonspecific inflammation (elevated white cells, CRP) and paired serology (antibody rise) can confirm recent infection retrospectively, but serology isn’t useful for immediate diagnosis and viral RNA in blood is uncommon except in severe cases.

Influenza is suspected when you have sudden high fever, chills, dry cough, sore throat, muscle aches, headache and marked fatigue. Confirm with a clinician‑collected nasal or throat swab: rapid antigen tests give quick results but PCR (molecular) testing is more accurate. See a healthcare provider for testing and early antivirals if symptoms are severe, you’re high‑risk, or symptoms begin within 48 hours.

Influenza A typically causes symptoms 1–4 days after exposure and acute illness lasts about 3–7 days in healthy adults. Fever and severe symptoms usually resolve within 3–4 days, but cough, weakness and fatigue can persist for 1–2 weeks or longer. High‑risk people or those with complications may experience a longer or more severe course and may need medical care.