How is influenza screening performed?

Influenza viruses belong to the family *Orthomyxoviridae* and are single-stranded, negative-sense, segmented RNA viruses. Based on differences in nucleoprotein (NP) and matrix protein (M), they are classified into four types: A, B, C, and D. Influenza viruses cause acute respiratory illness and are highly contagious. In clinical practice, influenza screening is particularly important and can be performed through the following steps:

I. History: Determine whether the patient had contact with individuals diagnosed with influenza prior to symptom onset.

II. Symptoms: Assess whether the patient exhibits influenza-like symptoms, such as high fever, headache, dizziness, cough, sore throat, and fatigue.

III. Diagnostic Tests:

1. Complete blood count (CBC): Influenza virus infection typically results in decreased total white blood cell (WBC) count and neutrophil percentage, along with an elevated lymphocyte percentage.

2. Etiological testing for influenza virus: Specific laboratory tests (e.g., rapid antigen detection, RT-PCR, or viral culture) can confirm influenza virus infection.

3. If pneumonia is suspected, chest X-ray or computed tomography (CT) may be performed to further evaluate disease severity and extent.