Complete Blood Count (CBC)
What is a complete blood count (CBC)?
A CBC test quantifies red and white blood cells and platelets in the blood, which can help diagnose medical conditions or diseases such as leukemia, thalassemia, and anemia. It is also beneficial for tracking progress or helping manage preexisting conditions like anemia, infection, or blood disorders.
A CBC measures various components of your blood, including:
- Red blood cell count
- The volume percentage of red blood cells (hematocrit)
- The levels of hemoglobin, the oxygen-carrying protein of red blood cells
- White blood cell count, including total amounts of white blood cells and percentages of specific types of white blood cells (CBC with differential)
- Platelet count
A doctor may order a CBC for routine health checkups or investigation of symptoms such as bruising, swelling, irritation, blood pressure problems, fever, dizziness, and fatigue.
Why do we need to check CBC? What are the benefits of examining the completeness of blood cells?
A CBC test can aid in suggesting diseases and conditions through blood component measurement. It is usually a part of an annual health examination program.
What disorders and diseases can the Complete Blood Count (CBC) test diagnose?
- Anemia
- Infections that lead to abnormally low or high white blood cell counts
- Bone marrow disorders
- Nutrient deficiencies
- Agranulocytosis (a condition of severely low white blood cell count)
- Cancer of white blood cells, such as leukemia and lymphoma
- Side effects of chemotherapy and medications.
Despite being very helpful, a complete blood count does not typically yield a definitive diagnosis. Additional tests are usually necessary to substantiate a diagnostic evaluation of a disease. For example, a complete blood cell may indicate an infection if the white blood cell count is high but cannot identify the causative infectious agent.
In preparation for the CBC test, what steps should be taken?
A CBC test does not require special preparation. However, fasting for a few hours before a test may be necessary in some circumstances.
What might happen when examining the completeness of blood cells?
During a test, a sample of your blood will be drawn from a vein and collected into a tube. The blood drawing may create a bruise at the needle puncture site, with pain lasting a few minutes. Lightheadedness or fainting may develop in some people after the needle sticks to draw blood.
What are the results of a CBC test?
The results of the CBC test are available on the same day. Abnormal results may necessitate follow-up tests.
The following are the normal ranges for a CBC:
- Red blood cell count:
- Male: 4.35 - 5.65 million/mm3
- Female: 3.92 – 5.13 million/mm3
- White blood cell count:
- Adult: 5,000-10,000/mm3
- Hemoglobin:
- Male (from 15 and over): 13.0 - 16.0 g/dL
- Female (from 15 and over): 11.5 - 15.5 g/dL
- Hematocrit:
- Male: 40 - 55%
- Female: 36 - 48%
- Platelet count:
- Adult: 150,000 - 400,000/mm3
For patients who are receiving chemotherapy, the results of a CBC markedly outside the normal ranges may necessitate adjustment in the administration regimen of the chemotherapeutic agents.
A Note from MedPark's Doctor
A complete blood count is a diagnostic test that assesses various blood components, including red and white blood cells and platelets. This test offers crucial insights into a person's overall health, helping identify conditions such as anemia, infections, and blood disorders. The CBC aids physicians in making informed diagnoses, monitoring ongoing treatments, and assessing a patient's response to medical interventions, enabling healthcare professionals to detect abnormalities and address potential health concerns, contributing significantly to preventive care and management of various medical conditions.
