What is CBC?
A complete blood count (CBC) test is a group of tests that provides information about blood cells like Red Blood Cells (RBC), White Blood Cells (WBC) and platelets. It is routinely performed to provide an overview of a patient’s general health status.
Why is CBC done?
- To monitor your overall health as part of a routine check-up
- To help detect a variety of disorders including infections, anemia, diseases of the immune system, and blood cancers
- To monitor an existing blood disorder
- To monitor treatment that is known to affect blood cells such as chemotherapy or radiotherapy
What does CBC Measure?
Blood is composed of blood cells suspended in blood plasma (yellowish-colored liquid). The blood cells include red blood cells (also called RBCs or erythrocytes), white blood cells (also called WBCs or leukocytes), and platelets (also called thrombocytes).
Red blood cells (RBCs) are the most abundant blood cells. RBCs contain hemoglobin which helps in the transportation of oxygen to the tissues. RBC count is the measurement of the number of RBCs in a given volume of blood.
Packed Cell Volume (PCV) or Hematocrit (Hct) is the measurement of the blood volume occupied by RBCs. It is expressed in percentage.
White blood cells (WBCs) are key components of the immune system and thus protect the body from various infections and cancers. Total Leucocyte count (TLC) is the measurement of the total number of leukocytes (WBCs) in a given volume of blood.
There are five types of WBCs:
Differential Leucocyte Count (DLC) determines the percentage of different types of WBCs.
Neutrophils, Basophils, and Eosinophils are called Granulocytes because of the presence of granules inside these cells.
Absolute count of different types of WBCs is the measurement of their absolute numbers in the given volume of blood.
Platelet count – Platelets (also called thrombocytes) are disc-shaped cell fragments without a nucleus that help in blood clotting. Platelet count is the measurement of the number of platelets in a given volume of blood.
Mean Platelet Volume (MPV) is a measurement of the average size of platelets.
PDW or platelet distribution width refers to the variation of platelet size distribution
Hemoglobin (Hb) – Hemoglobin (Hb) is a protein found in red blood cells (RBCs) that carries oxygen from the lungs to the body tissues, exchanges the oxygen for carbon dioxide, and then carries the carbon dioxide back to the lungs where it is exchanged for oxygen.
Mean Corpuscular Volume (MCV) is the average volume of a red blood cell.
Mean Corpuscular Hemoglobin (MCH) is the average amount of hemoglobin in the average red blood cell.
Mean Corpuscular Hemoglobin Concentration (MCHC) is the average concentration of hemoglobin in a given volume of red cells.
Red Cell Distribution Width Coefficient of variation (RDW CV)is a measurement of the variability of the red blood distribution curve and their mean size.
Interpreting CBC results
- Males: 13.2 – 16.2 gm/dL
- Females: 12.0 – 15.2 gm/dL
Red Blood Cell Count (RBC)
- Males: 4.3 – 6.2 million/μL
- Females: 3.8- 5.5 million/μL
- Infant/Child: 3.8- 5.5 million/μL
White Blood Cell Count (WBC)
- Differential Leucocyte Count
– Neutrophils – 35-80%
– Lymphocytes – 20-50%
– Monocytes – 2-12%
– Eosinophils – 0-7%
– Basophils – 0-2%
Platelet count (Plt) – 1.5 – 4.5 lacs/μL
- Males: 40-52%
- Females: 37-46%
- Child: 31-43%
Red Cell Distribution Width (RDW) – 35-47 fL
Mean Corpuscular Volume (MCV)
- Males: 82-102 fL
- Females: 78-101 fL
Mean Corpuscular Hemoglobin (MCH) – 27-34 pg
Mean Corpuscular Hemoglobin Concentration (MCHC) – 31-35 gm/dL
Mean Platelet Volume (MPV) – 6.0-9.5 fL
Meaning of Abnormal CBC Test Results
Decreased levels – Anemia
Increased levels – Polycythemia
Decreased levels – Aplastic anemia, Bone marrow disorders, Autoimmune conditions
Increased levels – Infections, Inflammatory disorders, Leukemia, Myeloproliferative disorders
- Neutrophil count
Decreased levels (Neutropenia) – Aplastic anemia, Autoimmune disorders, Drug reactions or Chemotherapy
Increased levels (Neutrophilia) – Acute bacterial infections, Inflammation, Burns
- Lymphocyte count
Decreased levels (Lymphopenia) – Bone marrow damage, Aplastic anemia, Autoimmune disorders
Increased levels (Lymphocytosis) – Acute viral infections, Tuberculosis, Lymphocytic leukemia
- Monocyte count
Decreased levels – Bone marrow damage
Increased levels (Monocytosis) – Chronic infections like tuberculosis, Bacterial endocarditis, Collagen vascular disorders, Inflammatory bowel diseases
- Eosinophil count
Decreased levels – Rare and medically insignificant
Increased levels (Eosinophilia) – Asthma, Allergies, Drug reactions, Parasitic infections
- Basophil count
Decreased levels – Medically insignificant
Increased levels (Basophilia) – Chronic myeloid leukemia (CML)
- Platelet count
Decreased levels (Thrombocytopenia) – Viral infections like dengue fever, bleeding or platelet disorders
Increased levels (Thrombocytosis) -Blood Loss, Chronic Infection or Inflammatory Disease, Removal of the spleen
Tests Included (22 tests)
- RDW CV
- RDW SD
- Mean Corpuscular Hemoglobin
- Mean Corpuscular Volume
- Mean Corpuscular Hemoglobin Concentration
- Absolute Leucocyte Count(includes 5 tests)
- Differential leucocyte Count(includes 5 tests)
- Platelet Count
- Total Leucocyte Count
- Packed Cell Volume
- Mean Platelet Volume
- Red Blood Cell Count