What is a Complete Blood Count (CBC)?

A complete blood count (CBC) is a kind of blood test that is done to assess a person’s overall health and diagnose a wide range of health disorders like leukemia, anemia and other infections.

A complete blood count (CBC) is a complete blood test that diagnose many components and features of a person’s blood which includes:

• Red Blood Cells (RBC), which carry oxygen
• White Blood Cells (WBC), which help in fighting against infections
• Hemoglobin, which is the oxygen carrying protein in the red blood cells
• Hematocrit, the proportion of RBC to the fluid component, or plasma present in blood
• Platelets, which aid in blood clotting

It is noteworthy that an increase or decrease in the CBC Test normal range may indicate an underlying medical condition that may need further medical evaluation.

What is the need for Complete Blood Count Test?

A complete blood test is done for many reasons, which are listed below:

• Review overall health – Doctor can recommend a complete blood test as a part of regular or routine medical examination to monitor general health.
• Inspect a medical condition – Doctor can suggest CBC blood test if the patient experiences fatigue, tiredness, fever, bruising, bleeding. A complete blood test may help in diagnosing the exact causes of these signs and symptoms.
• Monitor a specific medical condition – If the patient has been diagnosed with a blood disorder that influences his/her blood cell count, the doctor may suggest complete blood test to assess the medical condition.
• Monitor medical treatment – Doctor can propose a complete blood test to have an overall inspection of the patient’s health if he/she is taking some specific medications which can affect blood cell count.

So it can be said that a complete blood count test is done to monitor and evaluate overall health of the patient, to screen for some diseases, to diagnose certain medical condition, to evaluate and monitor changes in the body owing to any medical treatment.

If you are giving your blood sample for a complete blood count test, you can have your normal food before going for the test. But if you are going for additional tests, then your doctor might suggest CBC test fasting, where you are required to fast for a certain amount of time before going for the test. Your doctor will give you the specific instructions according to your health and required tests beforehand.

Complete blood count normal ranges chart different for different elements of blood. Having said that, it is also important to note that a CBC blood test is usually not a sure-shot diagnostic test. You may or may not require a follow-up after the CBC blood test if the results are not in the normal range. The reason for undergoing complete blood test is a key factor here. This can be understood with an example. If you are overall healthy and show no signs or symptoms of any kind of illness, if the results of CBC blood test are outside the prescribed normal range, there may not be any cause of concern and you might now even require a follow-up with the doctor post the test. Another example could be that if the CBC blood test report of a person undergoing cancer treatment are not in the normal range, an alternate treatment would be needed. In certain extreme cases, where the patient’s results are significantly above or less than the prescribed levels, he/she would be referred to a hematologist – doctor specializing in disorders of blood.

What can the findings of complete blood test indicate?

A typical blood test is done by taking a small blood volume of blood sample from the patient’s body and then evaluating it for different elements of blood, like white blood cells, hematocrit, hemoglobin, platelets, red blood cells, as well as specifying the dissemination of white blood cells into neutrophils, basophils, eosinophils, leukocytes and monocytes.

The results of CBC count can vary on the complete blood cell count. CBC that is too high or too low could indicate many health conditions, like:

• Iron deficiency
• Vitamin and mineral deficiency
• Heart ailments
• Autoimmune disorders
• Bone Marrow problems
• Cancer
• Reaction to a specific medication
• Inflammation or Infection

After a CBC blood test, findings in the below mentioned areas which are above or below the normal range might indicate a health problem:

• Red Blood Cell (RBC) Count, hemoglobin (amount of protein in red blood cells that carry oxygen) and hematocrit (percentage of blood that is made up of red blood cells). It is noteworthy that the results of these three elements- Red Blood Cell, hemoglobin and hematocrit are related as these measure aspects of your red blood cells. If the levels of these are below normal, the person might be having anemia. Anemia results in tiredness and weakness. There are a lot of causes for anemia, like low levels of some specific vitamins or iron, blood loss or an underlying cause. Certain cancer treatments like chemotherapy and radiation therapy can also cause a decrease in the number of red blood cell count.

A high count of RBC could happen because of the following reasons:

1. Dehydration or severe diarrhea
2. Kidney problem with high erythropoietin production
3. Low level of oxygen level in the blood for a prolonged time. This could be because of a heart or lung disease
4. Smoking

A low count of RBC or hematocrit could occur because of the following reasons:

1. Autoimmune diseases like lupus erythematosus or rheumatoid arthritis
2. Blood loss or hemorrhage
3. Bone marrow failure
4. Chronic kidney problem
5. Leukemia or other blood cancer
6. Long term infections like hepatitis
7. Inadequate diet and nutrition

• White Blood Cell (WBC) Count- A low white blood cell or leukopenia can be caused by a medical condition, like an autoimmune disorder which destroys WBC, cancer or bone marrow cancer. Certain cancer treatments like chemotherapy may result in a decrease in the number of white blood cells. Cancers that influence blood and bone marrow can also result in decline in the white blood cells count. Such kind of cancers include multiple myeloma, lymphoma and leukemia.

If lymphocytes and monocytes are higher than the normal range, there is a danger of certain kinds of cancer. It is noteworthy here that some cancer and their treatment can cause neutropenia. Neutropenia causes a decrease in the number of neutrophils, which can increase the chances of bacterial infection in a person.

Sometimes the doctor reduces the chemotherapy dosage to reduce the chances of developing a low count of neutrophil. The doctor can sometimes also give medication to increase white blood cells growth factors to increase human body’s production of neutrophils, especially when a patient develops high fever.

Some specific medications can also cause white blood cells to drop. It is also important to note that in the complete blood test if the white blood cell count is higher than normal, the person might be having an infection or inflammation. Else it could also indicate that the person may be having a bone marrow disease or a disorder in the immune system. A sharp increase in the white blood cell typically happens in response to a bacterial infection.

A low count of WBC or leukopenia could be because of the following reasons:

1. Autoimmune diseases
2. Bone marrow failure
3. Liver disease

A high count of WBC or leukocytosis could be due to the following reasons:

1. Infectious diseases
2. Blood cancer or leukemia
3. Inflammatory diseases
4. High level of emotional or physical stress
5. Tissue damage like burns

Low levels of hemoglobin could be because of the following factors:

1. Anemia of various types
2. Blood loss

• Platelet Count- Platelet count that is lower than the normal range (thrombocytopenia) or higher than the normal range (thrombocytosis) is usually a sign of an underlying medical problem. It could also be side effect of a medication. If the person is suffering from thrombocytopenia, he/she could be at a higher risk of bleeding as his/her body has fewer platelets to forma clot to stop bleeding. Alternatively, if a person has thrombocytosis, he/she would be at an increased risk for developing a blood clot that could be highly dangerous. It is observed that a certain cancer treatments like radiation therapy or cancer treatment may result in a decrease in the number of platelets. A sharp decline in the number of platelets is seen in patients who are suffering from cancer that involve the bone marrow. This can result in thrombocytopenia. Patients suffering from thrombocytopenia have a higher risk of bleeding or bruising as their platelet count is very low. If the platelet count falls very low, the doctor can advise blood transfusion.

For more specific information on the findings of the complete blood test if they are outside the normal range, it is important to speak to the doctor. Your doctor might suggest further health tests to evaluate your medical condition to confirm a diagnosis. You can visit Dr Lal PathLabs for a Complete Blood Cell count test or can book the test online from your smartphone by downloading Dr Lal PathLabs Official Android App.