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.
- The 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.
- 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 (RDW)is a measurement of the variability of red blood cell size
The following are normal complete blood count results for adults:
|Red blood cell count||Male: 4.35-5.65 trillion cells/L*
(4.35-5.65 million cells/mcL**)Female: 3.92-5.13 trillion cells/L(3.92-5.13 million cells/mcL)
|Hemoglobin||Male: 13.2-16.6 grams/dL***
(132-166 grams/L)Female: 11.6-15 grams/dL
|Hematocrit||Male: 38.3-48.6 percent
Female: 35.5-44.9 percent
|White blood cell count||3.4-9.6 billion cells/L
(3,400 to 9,600 cells/mcL)
|Platelet count||Male: 135-317 billion/L
(135,000 to 317,000/mcL)Female: 157-371 billion/L
(157,000 to 371,000/mcL)