Patient education: White blood cell differential (The Basics)

What is a white blood cell differential? — A white blood cell differential is usually part of a blood test called a complete blood count, or "CBC." It tells you how many of each of the different types of white blood cells you have. It also shows if you have any abnormal white blood cells.

Blood is made up of 3 main types of cells: red blood cells, white blood cells, and platelets. White blood cells help your body fight infection. There are 5 main types of white blood cells:

●Neutrophils

●Lymphocytes

●Monocytes

●Eosinophils

●Basophils

Blood cells are made in bone marrow.

Why might I get a white blood cell differential? — You might get a CBC with a white blood cell differential, sometimes called a "CBC with diff," as part of a regular check-up. If you had a CBC without a white blood cell differential, and it showed that 1 or more of your white blood cell counts are higher or lower than normal, your doctor will do a white blood cell differential to learn more.

This test might also be done if your doctor thinks that you might have a health problem. Examples include:

●Infection

●Inflammation

●Allergies

●Asthma

●An "autoimmune" disorder, such as rheumatoid arthritis or celiac disease

●A blood or bone marrow disorder

How do I prepare for a white blood cell differential? — For this test, you will get a "blood draw." Your doctor or nurse will tell you where to go for this. They might tell you to avoid eating or drinking for 8 to 12 hours before the test.

It might help to wear a short-sleeve shirt when you get your blood drawn. This makes it easier for the person drawing the blood to get to your arm.

What happens during a blood draw? — For the blood draw, a needle is used to take a small amount of blood from your arm (figure 1). Collecting the blood only takes a few minutes. The blood is then tested in a lab.

Tell the person who takes your blood:

●If you take "blood thinner" medicines or if you have a bleeding problem – They will make sure that your bleeding is under control before you leave.

●If you have a latex allergy – Some of the supplies used for blood draws might contain latex.

●If you have a preferred arm to use

Most of the time, getting blood taken does not cause problems. You might have a little soreness or bruising where the needle went in.

What do my results mean? — Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

If your white blood cell differential shows any abnormal results, your doctor or nurse will talk to you about what to do next. They might need to do more tests to figure out what the cause is. If the results are abnormal, you might have a health problem that is causing you to have too few or too many white blood cells.

If you do have a health problem, your doctor will work with you to come up with a plan for treatment.

More on this topic

Patient education: Complete blood count (CBC) (The Basics)
Patient education: Leukemia in adults (The Basics)
Patient education: Leukemia in children (The Basics)
Patient education: Rheumatoid arthritis (The Basics)
Patient education: Celiac disease (The Basics)
Patient education: Myelodysplastic syndromes (MDS) (The Basics)

Patient education: Rheumatoid arthritis symptoms and diagnosis (Beyond the Basics)
Patient education: Celiac disease in adults (Beyond the Basics)
Patient education: Celiac disease in children (Beyond the Basics)
Patient education: Myelodysplastic syndromes (MDS) in adults (Beyond the Basics)