How to Read Your Blood Count Levels

A complete blood count, or CBC, is a common test that is included almost any time you have basic blood work. While the numbers on your report may seem frightening at first, once you have a basic strategy for reading the results and general knowledge about what the test measures you will be able to better understand the numbers on the report.

Basic Strategy

1. Glance at the laboratory report and note any abnormalities. Most reports will have abnormal values reported in a separate abnormal column or flagged in some way.


2. Find the value that is reported as abnormal, and consider possible causes for the abnormality. 


3. Discuss further tests with your doctor to determine the cause of any abnormalities in your blood count. If the results seem suspicious based on your current health, repeat the test before acting on the abnormal results.

Understanding Specific Values

The CBC reports on the types of cells found in your blood. There are many values measured in the CBC, but the most important elements to understand include:

• White Blood Cells (WBCs)- These are the infection fighting cells in the blood. There are many types of white cells, but the reported number reflects the total count of all of these types.  The two most common causes of an increased white blood cell count are infection and inflammation , though there are other more serious possibilities. Causes of a decreased white count include certain diseases, bone marrow disorders, radiation therapy and chemotherapy. To reach a more in-depth understanding of white blood cell count abnormalities, your doctor will need to consider the types of white cells causing the increase or decrease. The count of each white blood cell type will be reported on your results sheet as the "differential" count.


• Red Blood Cells (RBCs)-These cells transport oxygen to the body. A decreased red blood cell count, called anemia, can be caused by many diseases, iron deficiency, bone marrow disorders and other conditions. An increased red blood cell count can be caused by high altitude, dehydration, congenital disorders, heart disease, kidney disease or other problems.


• Hemoglobin (Hb)-This is the molecule that carries oxygen within the red blood cells.  Hemoglobin count is influenced by red blood cell count, iron deficiencies and other factors. 


• Hematocrit (Hct)- This ratio of red blood cells to whole blood volume is usually used to evaluate anemia and dehydration.


• Platelets - These cellular fragments are extremely important in your ability to form blood clots. If you have platelet count abnormalities, your doctor will want to investigate your clotting potential further. This is especially true if you are preparing to have surgery.