A complete blood count (CBC) is a blood test that provides information about the different types and quantities of blood cells in your body. It’s a commonly done test that can help diagnose various health conditions, including infections, anemia, leukemia, and other blood disorders.

CBC tests usually measure the following parameters:

1. Red blood cells (RBCs): RBCs are responsible for carrying oxygen from the lungs to the rest of the body. CBC tests measure the number of RBCs, their size, and their hemoglobin content. Abnormal RBC counts or sizes can indicate various conditions, such as anemia, bleeding disorders, bone marrow problems, or kidney disease.
2. White blood cells (WBCs): WBCs are the cells of the immune system that help fight infections and other diseases. CBC tests measure the total number of WBCs, as well as the percentages of different types of WBCs, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Abnormal WBC counts can indicate infections, inflammation, allergies, autoimmune disorders, or leukemia.
3. Platelets: Platelets are tiny cells that help stop bleeding by forming clots. CBC tests measure the number of platelets in the blood. Abnormal platelet counts can indicate bleeding disorders, bone marrow problems, or other medical conditions.
4. Hemoglobin (Hb): Hemoglobin is the protein in RBCs that carries oxygen. CBC tests measure the amount of hemoglobin in the blood. Abnormal hemoglobin levels can indicate anemia, sickle cell disease, or other blood disorders.
5. Hematocrit (Hct): Hematocrit is the percentage of RBCs in the blood. CBC tests measure the Hct level to determine the amount of oxygen-carrying capacity of the blood. Abnormal Hct levels can indicate anemia, dehydration, or other medical conditions.

Normal values for each of these parameters may vary depending on age, gender, and other factors. However, generally, the following ranges can be considered normal:

• RBCs: 4.5 to 5.5 million cells/mcL (men) and 4.0 to 5.0 million cells/mcL (women)
• WBCs: 4,500 to 11,000 cells/mcL
• Platelets: 150,000 to 450,000/mcL
• Hemoglobin: 13.5 to 17.5 g/dL (men) and 12.0 to 15.5 g/dL (women)
• Hematocrit: 38.8% to 50.0% (men) and 34.9% to 44.5% (women)

Abnormal values for any of these parameters may indicate an underlying health condition. For example, a low RBC count may indicate anemia, while a high WBC count may indicate an infection or inflammation. Similarly, a low platelet count may indicate a bleeding disorder, and a low hemoglobin level may indicate iron deficiency anemia.

In conclusion, the CBC test is an essential tool for diagnosing and monitoring various health conditions. It measures several parameters, including RBCs, WBCs, platelets, hemoglobin, and hematocrit, and can provide valuable insights into your overall health. If you have concerns about your CBC results, talk to your healthcare provider for more information and guidance.