What your complete blood cell count means
A complete blood cell count (CBC) is a test that lets doctors look at your blood to get a better view of your overall health. The test measures the different components of your blood and their quantities — especially red and white blood cells. Based on these numbers, doctors can identify certain health conditions.
Doctors don’t always use a CBC to make a diagnosis, but it’s a good starting point. Abnormal numbers for any of the components could mean you have an underlying condition that needs further testing. Doctors can also use the results of a CBC to monitor a condition or figure out if a treatment for a condition is working.
Take a closer look at what information a CBC provides and how these tests are an important part of healthcare.
Understanding red blood cells
Red blood cells carry fresh oxygen from your lungs throughout your body. They also carry carbon dioxide back to your lungs. These cells are made in your bone marrow, which is located in the center of your bones. Doctors can determine the overall health of your red blood cells by looking at their size and shape.
The average red blood cell count for healthy men is between 4.7 and 6.1 million cells per microliter. The average red blood cell count for healthy women is between 4.2 and 5.4 million cells per microliter, according to Healthline. There are some conditions or medications that can affect your red blood cell count. That’s why a CBC can help doctors learn if an abnormal number of red blood cells is the cause.
On a CBC, you’ll see the total measure of red blood cells along with measurements of hemoglobin and hematocrit. Both of these give your doctor a closer look at your red blood cells and the percentage of blood made up of red blood cells.
Understanding white blood cells
White blood cells are the components of your blood that fight off infections. These cells make up a small part of your blood, but their job is important. Like red blood cells, these are also made in the bone marrow. There are several different types of white blood cells, and each has a different job. Some fight off parasites. Others attack bacteria and others combat viruses. Others work to make antibodies.
If you have a high number of white blood cells in your blood, then that signals to your doctor that your body is fighting off some sort of infection or inflammation. If your white blood cell count is low, then your body doesn’t have the defenses it needs to fight off infections. The normal range for a healthy person is 4,500 to 10,000 white blood cells per microliter of blood.
Platelets stop bleeding when you get a cut. Platelets stick together to form clots and repair damage to blood vessels. If your platelet level is too low, then you might bruise easily or have trouble controlling your bleeding if you get a cut. The normal number of platelets to look for in your CBC is between 140,000 to 450,000 cells per microliter, notes Mayo Clinic.
A closer look at your lab test results
Getting a CBC is simple. A nurse or other member of your healthcare team takes a sample of blood from your arm and sends it to the lab for testing. The lab measures the different components in your blood and sends the report back to your doctor. Often, your doctor provides you with a copy as well.
Your doctor goes over the results with you and explains what they mean. Each lab is different. Labs usually vary a little in what they consider a normal range. On the results, the lab should define what the normal range is next to what your measured range is. It should indicate if your count is high or low so that you can ask your doctor questions about what that means for your health.
Talk to your doctor
A CBC is a test that measures the components of your blood and is usually a part of your annual checkup. The number of red and white blood cells that you have in your blood can indicate a number of things about your health. It can also alert your doctor if you need more testing. Visit Mercy.com to learn more about CBCs.