Complete blood count (CBC) is a common blood test included in routine medical examinations. It is so common that every person might have had a CBC at least once in their lifetime. Diseases like anaemia, infections, immune system issues, blood cancers etc., can be detected early through a complete blood count test.
Another type of blood test called an erythrocyte sedimentation rate (ESR) can determine whether or not you have inflammation in your body. This test examines the rate at which red blood cells or erythrocytes fall (sediment), in a sample of blood that is placed in a tall, vertical tube. Inflammation is indicated by an increased sedimentation rate.
CBC is a vital comprehensive blood test that measures your white blood cells (WBC), red blood cells (RBC), and platelets (PLT) to assess each type of blood cell in your body. These blood cell types perform crucial functions, so this test is used to detect a range of health problems and monitor how different diseases or medical treatments like chemotherapy can affect the body.
What do different blood cells do?
- White Blood Cells (WBC): They help the body to fight against illnesses and infections.
- Red Blood Cells (RBC): They help in the transport of oxygen from lungs to body tissues.
- Platelets (PLT): They help to stop and prevent bleeding.
It is important to get tested and treated for certain diseases like leukaemia, anaemia, and infections using a CBC test because this test helps doctors to diagnose and treat patients effectively.
What are the normal levels of CBC?
CBC test is used to measure the following components of blood:
Red Blood Count: The number of red blood cells in a given amount of blood is known as the red blood cell count.
- The normal range for RBC count in males is 4.7 to 6.1 million cells/mcL.
- The normal range for RBC count in females is 4.2 to 5.4 million cells/mcL.
- Low levels of oxygen in the body may cause the red blood cell count to fall below the normal range.
- Low RBC counts might be caused due to malnutrition, anaemia, bleeding, cancer, kidney disease, liver disease, and medications used to treat cancer.
Haematocrit: Haematocrit, also referred to as Packed Cell Volume (PCV), determines the volume of blood that is occupied by the red blood cells.
- The normal range for haematocrit in males is 40.7% to 50.3%.
- The normal range for haematocrit in females is 36.1% to 44.3%.
- Lower than normal haematocrit percentage could indicate an iron deficiency.
- Higher than normal haematocrit percentage could be due to dehydration or diseases like bone cancer.
Total Leukocyte Count (TLC): TLC refers to the total amount of white blood cells in a given amount of blood.
- The normal range for WBC count in adults is 4,500 to 10,000 cells/mcL.
- Lower than normal white blood cell count may be indicative of a bone marrow disorder, an autoimmune disorder, or cancer.
- Higher than normal white blood cell count may be indicative of an inflammation, an infection, or a reaction to a medication.
Platelet Count: The number of platelets in a given volume of blood is known as the platelet count.
- The normal range for platelet count in adults is 150,000 to 450,000/dL.
- Decreased platelet counts may be caused due to conditions like leukaemia, rheumatoid arthritis, lupus, and medication side effects.
- Increased platelet counts may be caused due to clotting disorders like thrombocythemia, certain cancers, infections etc.
Mean Platelet Volume (MPV): The average platelet size found in blood is measured by MPV.
- A normal MPV blood test is 7 fL to 9 fL for adults.
- Higher test result indicates that your platelets are larger than normal. Newly produced platelets are larger than older platelets. Conditions resulting in higher MPV are cancer, diabetes, cardiovascular disease, hyperthyroidism, vitamin B12, vitamin D or folate deficiency etc.
- Lower test result indicates that your platelets are smaller than normal. Low MPV could be an indication that your bone marrow isn't making sufficient new platelets.
Platelet Distribution Width (PDW): The variation in platelet size distributions that can be found in blood is known as PDW.
- A normal PDW result is 9.2 fL to 16.7 fL for adults.
- Normal PDW indicates that the platelets are generally the same size.
- A high PDW means that platelet size varies significantly. It may be caused due to platelet activation and has been linked to some cancers and vascular diseases.
Haemoglobin (Hb): Red blood cells contain the protein Hb, which transports oxygen from the lungs to body tissues.
- The normal range for Hb in males is 13.8 to 17.2 gm/dL
- The normal range for Hb in females is 12.1 to 15.1 gm/dL
- Low blood oxygen levels (hypoxia) are the main cause of high haemoglobin levels, this is usually caused due to bone marrow diseases.
- If your haemoglobin level is lower than normal, you likely have anaemia, which is characterized by a low red blood cell count.
Mean Corpuscular Volume (MCV): The size of red blood cells in blood is measured by the MCV.
- A normal MCV test result is 80 fL to 95 fL in adults.
- Lower than normal MCV may be caused due to iron deficiency.
- Higher than normal MCV may be caused due to vitamin B12 and vitamin B9 deficiency.
Mean Corpuscular Haemoglobin (MCH): MCH is the average amount of haemoglobin found in each red blood cell.
- A normal MCH test result is 27 to 31 pg/cell in adults.
- Lower than normal MCH may be caused due to iron deficiency.
- Higher than normal MCH may be caused due to vitamin B12 and vitamin B9 deficiency.
Mean Corpuscular Haemoglobin Concentration (MCHC): MCHC is the average haemoglobin concentration present in red blood cells.
- A normal MCHC test result is 32 to 36 gm/dL in adults.
- Higher than normal MCHC value is commonly observed when haemoglobin is more concentrated within your red blood cells. This is caused due to conditions like haemolytic anaemia and hereditary spherocytosis.
- Lower than normal MCHC value may be caused due to cancer, parasitic infections, lead poisoning etc.
Red blood cell Distribution Width (RDW): RDW measures the differences in red blood cell volume and size.
- A normal RDW is 12% to 15% in adults.
- Higher than normal RDW might be a sign of nutrient deficiency or anaemia.
- Lower than normal RDW is typically not concerning and is not linked to any particular hematologic disorder.
CBC blood test is helpful in assessing a person's overall health. This test can aid in the detection of different diseases and infections. Health care professionals use CBC test result to monitor patient’s health, screen for diseases and plan the course of treatment. Thus, getting your CBC test done is recommended to detect and treat conditions like inflammatory health conditions, nutritional deficiencies, certain cancers etc.
