A CBC with differential (CBC with diff) is a blood test that measures the different types of blood cells in your body and their characteristics. It provides a comprehensive overview of your blood cell composition, helping doctors diagnose and monitor various health conditions.
Components of a CBC with Diff
The Complete Blood Count (CBC) itself measures:
- Red Blood Cells (RBCs): These carry oxygen throughout your body. The CBC measures the number of RBCs, their size (MCV), hemoglobin (oxygen-carrying protein), and hematocrit (percentage of blood volume made up of RBCs).
- White Blood Cells (WBCs): These fight infection. The total number of WBCs is measured.
- Platelets: These help your blood clot. The number of platelets is measured.
The "diff" or "differential" part of the test breaks down the different types of WBCs:
- Neutrophils: Fight bacterial infections.
- Lymphocytes: Fight viral infections and play a role in immune responses.
- Monocytes: Engulf and destroy debris and microorganisms.
- Eosinophils: Fight parasitic infections and are involved in allergic reactions.
- Basophils: Release histamine and other chemicals involved in inflammation.
Why is a CBC with Diff Performed?
A CBC with diff is ordered for a variety of reasons, including:
- To evaluate overall health: As part of a routine checkup.
- To diagnose infections: Elevated or decreased WBC counts can indicate an infection.
- To diagnose anemia: Low RBC counts can indicate anemia.
- To diagnose bleeding disorders: Low platelet counts can indicate a bleeding disorder.
- To monitor treatment for blood disorders: Such as leukemia or lymphoma.
- To monitor side effects of medications: Some medications can affect blood cell counts.
- To investigate symptoms: Such as fatigue, fever, inflammation, or unexplained weight loss.
How to Interpret the Results
The normal ranges for blood cell counts can vary slightly depending on the laboratory performing the test. Your doctor will interpret your results in the context of your medical history, physical exam, and other test results. Abnormal results may indicate a variety of conditions, and further testing may be necessary to determine the cause. For example:
- High WBC count: May indicate infection, inflammation, or leukemia.
- Low WBC count: May indicate a viral infection, bone marrow disorder, or autoimmune disease.
- High neutrophil count: May indicate a bacterial infection.
- High lymphocyte count: May indicate a viral infection or leukemia.
- Low RBC count: May indicate anemia or blood loss.
- High platelet count: May indicate a clotting disorder.
- Low platelet count: May indicate a bleeding disorder or autoimmune disease.
In summary, a CBC with differential is a valuable diagnostic tool that provides detailed information about your blood cell composition and helps doctors diagnose and monitor a wide range of health conditions.
