Blood Tests for Cough and Related Issues
Persistent cough? Discover how blood tests like CBC, CRP, and IgE help diagnose infections, allergies, or underlying conditions. Know when to seek medical help.
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Introduction
Coughing is a common symptom that can be caused by various factors, from a simple cold to more serious health conditions. While most coughs resolve on their own, persistent or severe coughing may require medical evaluation. One of the ways doctors diagnose the underlying cause of a chronic or worrisome cough is through blood tests.
This article explores how blood tests support the diagnosis of persistent coughs, what they reveal, and when it’s time to consult a doctor.
Why Are Blood Tests Needed for a Cough?
A cough can be triggered by infections, allergies, asthma, acid reflux, or even more serious conditions like lung disease or heart problems. Blood tests help doctors:
- Identify infections, whether bacterial or viral
- Check for inflammation or allergies
- Assess immune system function
- Detect underlying conditions like anaemia or autoimmune disorders
If your cough lasts more than 2-3 weeks, is accompanied by fever, weight loss, blood in mucus, or difficulty breathing, your doctor may recommend blood tests along with other diagnostic procedures like chest X-rays or sputum tests.
Consult Top Specialists for Personalised Health Advice
Common Blood Tests for Cough and Respiratory Issues
Several blood tests can provide important clues about what’s behind your cough. Here’s a breakdown of the most commonly used ones.
1. Complete Blood Count (CBC)
A CBC measures different components of your blood, including:
- White Blood Cells (WBCs) – High levels may indicate an infection, whether bacterial or viral.
- Red Blood Cells (RBCs) & Haemoglobin – Low levels could suggest anaemia, which may cause fatigue and worsen breathing difficulties.
- Platelets – Abnormal levels may indicate bleeding disorders or infections.
2. C-Reactive Protein (CRP) & Erythrocyte Sedimentation Rate (ESR)
These tests detect inflammation in the body, which could be due to:
- Infections like pneumonia or bronchitis
- Autoimmune conditions, such as rheumatoid arthritis, that affect the lungs
3. Allergy Testing
If your cough is due to allergies like dust, pollen, or pet dander, an Immunoglobulin E (IgE) test can help identify triggers.
4. Procalcitonin Test
This test helps differentiate between bacterial and viral infections. High procalcitonin levels often suggest a bacterial infection requiring antibiotics.
5. D-Dimer Test
If a cough is accompanied by chest pain and breathing difficulties, doctors may check for pulmonary embolism—a blood clot in the lungs—using this test.
6. Tuberculosis (TB) Test (Quantiferon Gold or T-Spot)
Persistent cough with night sweats, weight loss, and fever may require TB testing. Blood tests may help in early detection.
What Do Abnormal Results Mean?
Once your test results are in, your doctor will interpret them based on what the numbers suggest.
- High white blood cells: Possible bacterial or viral infection
- Low haemoglobin: May suggest anaemia
- High CRP/ESR: Inflammation, possibly from infection or autoimmune disease
- Positive TB test: Requires further evaluation with chest X-ray or sputum tests
When Should You See a Doctor?
Consult a healthcare provider if your cough:
- Lasts more than 3 weeks
- Is severe or worsening
- Includes blood in the mucus
- Comes with fever, unexplained weight loss, or breathing difficulty
You can book a consultation or lab test through Apollo 24|7 for quick and accurate diagnosis.
Tips to Manage Cough Symptoms at Home
While blood tests help diagnose the cause, you can also try these remedies:
- Stay Hydrated – Warm water, herbal teas, and soups help soothe the throat.
- Use a Humidifier – Moist air reduces throat irritation.
- Avoid Irritants – Smoke, dust, and strong perfumes can worsen coughing.
- Honey & Ginger – Natural remedies to ease throat irritation.
- Over-the-Counter Medicines – Cough suppressants or expectorants—always consult a doctor first.
Final Thoughts
A cough is usually harmless, but if it persists, blood tests can help uncover the root cause. Early diagnosis ensures proper treatment and prevents complications.
If you’re experiencing a prolonged or severe cough, don’t ignore it—get tested and consult a doctor. Apollo 24|7 offers convenient online doctor consultations and home blood test services for quick and reliable healthcare solutions.
Consult Top General Physicians
Consult Top General Physicians
Dr. Syed Ismail Ali
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7 Years • MBBS
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Consult Top Specialists for Personalised Health Advice
Dr. Syed Ismail Ali
General Practitioner
7 Years • MBBS
Hyderabad
Apollo 24|7 Clinic, Hyderabad
Dr D M Karthik
General Practitioner
4 Years • MBBS, Fellowship in Diabetes Mellitus, Advance certificate in Diabetes Mellitus, Derma Nutrition Certification
Visakhapatnam
Apollo 24|7 Clinic - Andhra Pradesh, Visakhapatnam
Dr. Mohammed Kamran
General Practitioner
5 Years • MBBS, FIDM
Nashik
Apollo 24|7 Clinic - Maharashtra, Nashik
Dr. Suraja Nutulapati
General Physician/ Internal Medicine Specialist
10 Years • MBBS, MD (Internal Medicine)
Hyderabad
Apollo 24|7 Clinic, Hyderabad
(875+ Patients)
Dr. D Bhanu Prakash
General Practitioner
10 Years • MBBS, AFIH, Advanced certificate in critical care medicine, Fellowship in critical care medicine
Hyderabad
Apollo 24|7 Clinic, Hyderabad
