How is Influenza A diagnosed?
Jan 09, 2025
Source: Cainiu Health
Dr. Ren Yi
Introduction
Influenza A, also known as Type A flu, is typically diagnosed through a comprehensive evaluation including symptom observation, influenza A virus antigen testing, influenza virus nucleic acid testing, serological testing, and viral isolation and culture. If any abnormalities are detected, prompt medical attention is recommended. It is also advised to maintain a healthy lifestyle with regular作息 (作息 should be replaced with appropriate English term such as "routine" or "schedule"), ensure adequate sleep, improve dietary habits, adjust physical condition, and maintain overall health.
Influenza A, commonly known as Type A flu, is typically diagnosed through comprehensive evaluation of symptoms, influenza A virus antigen testing, influenza virus nucleic acid testing, serological testing, and viral isolation and culture. If any abnormalities are noticed, timely medical consultation is recommended. Detailed analysis is as follows:
1. Symptom observation: Patients with influenza A often present with high fever, cough, runny nose, sore throat, headache, muscle pain, fatigue, and other symptoms. Some patients may also experience gastrointestinal symptoms such as vomiting and diarrhea.
2. Influenza A virus antigen detection: This test uses nasal or throat swab samples and employs rapid detection techniques such as immunochromatography to detect the presence of influenza A virus antigens. It is simple and quick to perform, with results usually available within 15-30 minutes. However, its accuracy is slightly lower compared to nucleic acid testing, and false-negative results may occur.
3. Influenza virus nucleic acid testing: This method uses respiratory specimens such as throat or nasal swabs and employs polymerase chain reaction (PCR) technology to detect the presence of influenza A virus nucleic acid. This method offers high sensitivity and specificity, enabling accurate detection of the influenza A virus, although the testing process takes relatively longer.
4. Serological testing: This primarily detects influenza A virus-specific antibodies in the patient's serum. It usually requires collecting two blood samples—one during the acute phase and another during the convalescent phase. A fourfold or greater increase in antibody titer during the convalescent phase compared to the acute phase supports a retrospective diagnosis of influenza A.
5. Virus isolation and culture: This involves inoculating collected respiratory specimens into specific cell cultures to observe for the growth of the influenza A virus. The method requires strict laboratory conditions and is generally not used as a routine diagnostic method, being mainly employed for research or special circumstances requiring definitive diagnosis.
It is recommended to maintain a healthy lifestyle, ensure adequate sleep, improve dietary habits, regulate physical condition, and promote overall health.
