A Complete Blood Count (CBC) is one of the most commonly ordered blood tests in India. Yet, most patients receive their reports unsure of what the numbers actually mean. This guide breaks down each parameter in plain language.
What is a CBC Test?
A CBC measures several components of your blood — red blood cells (RBCs), white blood cells (WBCs), and platelets. It helps doctors identify a wide range of conditions including anemia, infections, clotting disorders, and even some cancers.
Key Parameters Explained
1. Hemoglobin (Hb)
Hemoglobin is the protein in red blood cells that carries oxygen throughout your body.
- Normal range (Men): 13.5–17.5 g/dL
- Normal range (Women): 12.0–15.5 g/dL
- Low hemoglobin indicates anemia and may cause fatigue, shortness of breath, and dizziness.
- High hemoglobin can indicate dehydration or conditions like polycythemia vera.
2. Red Blood Cell Count (RBC)
RBCs carry oxygen from the lungs to the rest of the body. The count tells you how many red blood cells are present in a volume of blood.
- Normal range: 4.7–6.1 million cells/μL (men); 4.2–5.4 million cells/μL (women)
3. White Blood Cell Count (WBC / Leukocyte Count)
WBCs are your immune system's soldiers. An abnormal count can signal infection, inflammation, or immune disorders.
- Normal range: 4,500–11,000 cells/μL
- High WBC (leukocytosis): Often suggests infection, stress, or inflammation.
- Low WBC (leukopenia): May indicate bone marrow issues or autoimmune conditions.
4. Platelet Count
Platelets are responsible for blood clotting. Both high and low platelet counts can be dangerous.
- Normal range: 150,000–400,000 platelets/μL
- Low platelets (thrombocytopenia): Risk of excessive bleeding. Can be caused by dengue, viral infections, or liver disease.
- High platelets (thrombocytosis): May increase clotting risk.
5. MCV (Mean Corpuscular Volume)
MCV measures the average size of your red blood cells. It helps classify the type of anemia:
- Low MCV: Iron-deficiency anemia or thalassemia
- High MCV: Vitamin B12 or folate deficiency anemia
When Should You Get a CBC?
Your doctor may order a CBC if you have:
- Fatigue, weakness, or shortness of breath
- Signs of infection (fever, chills)
- Unexplained bruising or bleeding
- As part of a routine annual health checkup
- Monitoring existing blood conditions