Complete Blood Count (CBC) Test and Sickle Cell Disease
CBC Test and Sickle Cell Disease
A complete blood count (CBC) test measures the number of cells in the blood, including red blood cells, white blood cells, and platelets. A CBC also measures reticulocytes (immature red blood cells) and hemoglobin. A CBC with differential gives more information about the types and numbers of white blood cells.
Children with sickle cell disease have abnormal red blood cells. Other blood cells may also be abnormal. That is why it is vital to monitor blood cells regularly.
If your child has sickle cell disease , they will need regular blood tests to monitor blood cell counts and other components of their blood. This information will help your care team monitor your child’s condition and know if treatments are working.
The number of blood cells, their size, and types in a healthy person usually falls within a range of numbers. This is called a reference range or standard range. Your doctor compares your child’s results to these ranges. Normal ranges can vary based on your child’s age, sex, and other factors.
Sickle cell disease can cause your child’s lab values to be outside the normal range. Review your child’s test results with your care team. They can explain the numbers and what they mean for your child.
Red blood cell (RBC) count
Red blood cells carry oxygen from the lungs all around the body. In sickle cell disease, red blood cells are hard, sticky, and shaped like a banana (sickle-shaped). Sickle cells also break down or die faster than normal red blood cells. This causes anemia, or low numbers of red blood cells.
Sickle cell disease causes red blood cells to become shaped like a banana or sickle.
White blood cell (WBC) count
White blood cells help fight infection. Sickle cell disease may lead to increased inflammation in the body which can directly affect white blood cells. Your child may have a white blood cell count that is higher than normal. Also, illness and some medicines can make your child’s white blood cell count go up or down for a short time. A low white blood cell count puts your child at higher risk for infection and can make it harder to heal from an illness.
Platelet count
Platelets are blood cells that help the blood to clot and stop bleeding. If your child has a low platelet count, they may bruise or bleed more easily. Sickle cell disease does not usually cause low platelet levels.
Hemoglobin
Hemoglobin is an iron-rich protein in the red blood cells that carries oxygen to the body’s tissues and organs. People with sickle cell disease have an abnormal kind of hemoglobin called sickle hemoglobin or hemoglobin S. Abnormal hemoglobin S causes red blood cells to:
Form a banana shape
Become sticky and stiff
Clog the small blood vessels in the body
Not last as long as they should
Break apart
It is important to know your child’s hemoglobin levels. The numbers will change due to the disease, treatments, and other factors.
Hematocrit (HCT or PCV)
Hematocrit (HCT or PCV) is a measure of how much space red blood cells take up in the blood compared to plasma and other cells. Hematocrit is measured as a percentage. In sickle cell disease, red blood cells typically do not last as long. This can cause hematocrit levels to decrease.
Reticulocyte count
A reticulocyte count is the number or percentage of young red blood cells in the blood. A person with sickle cell disease may have a higher reticulocyte count than normal. This is because their body must make more new red blood cells to replace the sickle cells that do not live as long.
Mean corpuscular volume (MCV)
The mean corpuscular volume (MCV) is the average size of red blood cells. This can vary based on:
The sickled shape of the red blood cells
The chronic breakdown and production of new red blood cells
Other conditions such as iron deficiency
Hydroxyurea therapy, which can increase MCV
Absolute neutrophil count (ANC)
Anabsolute neutrophil count (ANC) is a measure of the number of neutrophils, a type of white blood cells that fight bacterial and fungal infections. Having low neutrophil counts is known as neutropenia. If your child has neutropenia, they may get infections more easily and recover more slowly.
Questions to ask your care team
How often will my child need routine blood tests?
How will I get a copy of my child’s lab results?
What do the test results indicate about my child’s health?
Are any of the lab values outside of the normal range or the range that you expect?
What do my child’s results mean for their current treatment plan?
How does hydroxyurea affect my child’s labs?
What is my child’s baseline hemoglobin?
Will my child need additional tests?
Key points about blood counts and sickle cell disease
When your child has sickle cell disease, it is important to monitor their blood cell counts regularly.
A complete blood count (CBC) test measures many aspects of your child’s blood to get a closer look at what is going on in their body.
Your care team uses CBC results and other lab tests to monitor your child’s sickle cell disease and how your child responds to treatment.
Review your child’s test results with your care team. They can explain the numbers and what they mean for your child.
A complete blood count (CBC) measures red blood cells, white blood cells, and platelets in the blood. Learn more about CBC and differential blood tests.
