Which blood test indicator shows Type A or Type B influenza?

Apr 24, 2025 Source: Cainiu Health

Dr. Ren Yi

Introduction

For blood tests for Type A and Type B influenza, key indicators include white blood cell count in routine blood tests, lymphocyte count in routine blood tests, C-reactive protein, procalcitonin, and influenza virus-specific antibodies. In daily life, it is important to maintain personal hygiene by washing hands frequently with soap or hand sanitizer, thoroughly cleaning according to the seven-step handwashing technique, especially after touching public items, before meals, and after using the toilet.

Generally speaking, "Jia Liu" refers to influenza A, and "Yi Liu" refers to influenza B. When testing for influenza A or B, blood tests mainly examine the white blood cell count in the complete blood count (CBC), lymphocyte count in the CBC, C-reactive protein (CRP), procalcitonin (PCT), and influenza virus-specific antibodies. Detailed explanations are as follows:

1. White Blood Cell Count in Complete Blood Count

During infection with influenza A or B, the white blood cell count is usually normal or decreased. This is because the immune response triggered by the viral infection shifts the immune system's focus toward fighting the virus, thereby altering the production and release patterns of white blood cells. Consequently, the peripheral blood white blood cell count does not significantly increase and may even decrease due to factors such as viral suppression of bone marrow hematopoietic function.

2. Lymphocyte Count in Complete Blood Count

Patients may experience a decrease in lymphocyte count. The influenza virus primarily invades respiratory epithelial cells and also affects the function and number of lymphocytes. Viral infection leads to lymphocyte damage and increased apoptosis, resulting in a decline in peripheral blood lymphocyte count, which reflects the impact of the virus on the body's immune cells.

3. C-Reactive Protein (CRP)

CRP levels generally show a mild increase. CRP is an acute-phase reactant protein whose production by the liver increases during inflammation. After the human body is infected with influenza A or B virus, an inflammatory response is triggered, stimulating CRP synthesis. However, the degree of elevation is typically not as pronounced as during bacterial infection, making CRP a useful reference indicator for distinguishing between viral and bacterial infections.

4. Procalcitonin (PCT)

PCT is a glycoprotein without hormonal activity that significantly increases during systemic bacterial infections. Influenza A and B are viral infections, so PCT levels typically do not rise significantly. However, when influenza is complicated by bacterial infection, PCT levels may markedly increase, aiding in the assessment of possible co-infection.

5. Influenza Virus-Specific Antibodies

These include IgM and IgG antibodies. IgM antibodies are produced early in infection and generally can be detected 3-5 days after symptom onset, indicating a recent infection. IgG antibodies appear later, usually increasing around 10-15 days after infection and persisting for a longer duration in the body. They are useful for retrospective diagnosis and epidemiological investigations. Detecting these specific antibodies can assist in diagnosing infection with influenza A or B.

In daily life, attention should be paid to personal hygiene, frequent handwashing using soap or hand sanitizer, and thoroughly washing hands following the seven-step handwashing technique, especially after touching public items, before meals, and after using the toilet. Additionally, maintaining good indoor air circulation and regularly opening windows for ventilation can help reduce the likelihood of virus transmission.

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Symptom Differences Between Influenza A and Influenza B

Influenza A refers to type A influenza, and influenza B refers to type B influenza. Generally, differences in symptoms between type A and type B influenza include variations in fever severity, headache intensity, cough characteristics, sore throat severity, and gastrointestinal symptoms. It is recommended to maintain good personal hygiene habits in daily life, such as frequent handwashing and keeping indoor areas well-ventilated, which can help prevent influenza.

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What kind of medication is oseltamivir?

Oseltamivir is generally classified as a neuraminidase inhibitor antiviral medication, primarily used for the treatment of influenza A and B. It works by specifically inhibiting the activity of neuraminidase, preventing the release of the virus from infected cells, effectively suppressing the viral replication process and reducing viral spread within the body, thereby achieving the purpose of treating and preventing influenza.

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What is Oseltamivir Granules?

Under normal circumstances, Oseltamivir Phosphate Granules are antiviral medications. The main active ingredient in Oseltamivir Phosphate Granules is oseltamivir phosphate, a neuraminidase inhibitor that works by inhibiting the neuraminidase activity on the surface of the influenza virus. This action prevents the release and spread of the virus and is primarily used for the treatment of influenza A and B.

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What are the symptoms of influenza A and B?

Under normal circumstances, influenza A and B refer to influenza type A and type B. Symptoms of both influenza A and B include fever, headache, muscle pain, cough, and fatigue. The symptoms and underlying mechanisms of influenza A and B primarily involve the body's systemic inflammatory response triggered by the virus, damage to the respiratory and gastrointestinal mucosa, and the body's immune response.