What Is a Complete Blood Count (CBC) Test and Why Is It Done?
The CBC blood test is the most common way to routinely prescribe a blood test in a doctor’s office and provides valuable information about the different kinds of cells in blood, which can help physicians assess a patient’s general health. Since a number of health conditions can affect blood cells, CBCs are frequently the first step to diagnosing a health condition when symptoms are unclear or monitoring an ongoing health issue.
Additionally, as an easy test to conduct and widely produced throughout the world, CBCs also play a critical role as the initial screening and diagnosis of various illnesses.
Table of Content:
What Is a CBC Blood Test?
- Basic Results for CBC Testing
- Why Is a CBC Test Done?
- Interpreting Abnormal CBC Results
- Who Should Use a CBC Test?
- When Should You Have Your CBC Test (including Complete Blood Count Test) Performed?
- Why is it critical to have your CBC results interpreted correctly?
- Conclusion:
What Is a CBC Blood Test?
A CBC measures how many and how healthy different parts of the blood, such as the amount of hemoglobin, hematocrit, platelets, etc., are.
These parts of blood serve many important functions, including delivering oxygen to every cell in the body, fighting infection, preventing blood loss, etc.
In most cases, no special preparation is necessary for taking a CBC; however, a small amount of blood (drawn from a vein) is required in order to perform the test. The CBC results will contain both numerical values and a set range to compare to so that healthcare professionals can determine whether blood cells are within normal limits.
Basic Results for CBC Testing
Basic Results for CBC Testing
A red blood cell (RBC) count is the total number of RBCs in the blood. The CBC includes RBC count as well as related parameters such as hemoglobin concentration (Hgb) and hematocrit percentage (Hct). Abnormal RBC counts may be indicative of anemia, dehydration, or some type of bone marrow problem.
Hemoglobin Content
Hemoglobin (Hgb), which is found in RBCs, binds oxygen and transports it to the body’s tissues. Decreased Hgb usually indicates an anemic condition, whereas increased Hgb may occur in chronic lung disease or following dehydration.
Volume of Red Blood Cells
Hematocrit percentage (Hct) is a measure of the total volume of blood occupied by RBCs. This result can help determine if the blood is either too dilute or too concentrated.
White Blood Cell Count
WBCs are part of the immune system. A CBC includes a total count of WBCs and may provide a breakdown of different types of WBCs (the differential). Increased WBC counts are typically associated with infection, inflammation, or stress; decreased WBC counts may indicate immune system dysfunction or certain bone marrow disorders.
Platelets
Platelets are cells that allow blood to clot and prevent excessive bleeding. A high or low number of platelets in the blood can result in blood clotting disorders or an increased chance of developing a blood clot.
Why Is a CBC Test Done?
CBC Tests are performed for multiple purposes, including:
1. To measure a person's overall health
A CBC test is often included as part of a routine medical exam to determine the general health status of a patient and to potentially find a health problem early, even though the patient does not have any apparent symptoms.
2. To diagnose medical conditions
Some medical conditions that can be diagnosed using CBC Testing include:
- Anemia
- Infections
- Inflammatory Conditions such as:
- Rheumatoid Arthritis
- Medically induced Inflammation (e.g., Healthcare-Associated Infections)
- Self-Medicated Inflammation (e.g., Arthritis, Crohn’s Disease, etc.)
- Autoimmune Diseases
- Blood Disorders (e.g., Leukaemia)
- Immune Disorders such as:
- Immune deficiency syndrome
- Weakened immune systems due to various causes
A CBC test is typically one of the first tests ordered when a patient presents with symptoms of fatigue or weakness, fever, unexplained weight loss, bruising, and so forth.
3. To monitor the progress of ongoing conditions
For example, patients with a chronic illness such as Anemia or an Autoimmune Disease will likely need CBC tests performed regularly in order to monitor the progress of their disease or their response to treatment.
4. To evaluate the effects of certain medications
Certain medications, including Chemotherapy and some Antibiotics, may have a negative impact on the patient’s production of blood cells. Therefore, a CBC test is performed to assess the negative effects of the medication and determine whether to change the medication or continue with it.
5. Assessing Nutritional Deficiencies
Low red blood cells (RBCs) or hemoglobin levels may indicate iron, vitamin B12, and/or folate deficiency. The sooner you discover the nutritional deficiency, the quicker you can begin to correct the issue.
Interpreting Abnormal CBC Results
Abnormal CBC results need to be taken into consideration in conjunction with other factors, such as age, gender, medical history, and symptoms. A small amount of elevated or decreased CBC readings does not mean you have a medical problem.
- Low RBCs or hemoglobin levels could indicate anemia (low red blood cells) or blood loss.
- High levels of white blood cells (WBCs) are typically due to either infection or inflammation in the body.
- Low levels of WBCs could indicate an individual has a decreased immune system response.
- Individuals with a low platelet count have an increased risk of bleeding.
- High platelet counts may indicate inflammation or a problem with the bone marrow.
If anything abnormal is seen on your CBC, further testing will be necessary to determine the cause of any abnormalities.
Who Should Use a CBC Test?
Individuals recommended for a CBC test may include:
- Individuals who have unexplained fatigue or weakness.
- Individuals who have multiple infections without a known cause.
- Individuals with frequent bruising and/or bleeding.
- Individuals scheduled for surgery.
- Individuals with long-term illnesses (i.e., cancer, diabetes).
- Individuals undergoing regular health check-ups for the purpose of prevention.
Everyone can utilize a CBC; it is safe and effective for individuals of all ages.
Why is it critical to have your CBC results interpreted correctly?
Having accurate results from a CBC test begins with collecting a blood sample correctly, using validated lab standards and having qualified healthcare providers interpret the test results. The actual procedure of how to collect a sample can differ from one lab to the next. You must use a facility that has a certification for performing diagnostic testing so that you receive an accurate report on your CBC findings.
At Sikund Diagnostic, we provide CBC testing as part of our pathology services, using standard laboratory protocols and quality assurance processes. Your healthcare provider will help you understand your CBC test results and whether further evaluation of your health status may be required.
When Should You Have Your CBC Test (including Complete Blood Count Test) Performed?
Healthy patients typically get their complete blood counts (CBC) done at routine check-ups, but healthcare providers will recommend more frequent CBC tests for people who are diagnosed with chronic illnesses.
Conclusion
A complete blood count test provides healthcare providers with very important information about a person’s overall health status and is considered a basic laboratory test. In fact, the test helps identify potential infections, anemia, immune-related disorders, and other health conditions early on. Although the test itself is very straightforward, the data obtained from the CBC test can significantly enhance the effectiveness of preventive medicine, diagnostic testing, and ongoing monitoring of your health. You should always discuss your CBC test results with your qualified healthcare provider to ensure they are appropriately interpreted and that you are making an informed decision about your overall health status.