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White Blood Cell Differential: About This Test

What is it?

A white blood cell differential counts the different types of white blood cells in a blood sample. There are five major kinds of white blood cells. The numbers of each type of white blood cell give important information about your immune system.

Why is this test done?

The test helps to measure how the body is responding to different types of infections. It can also help measure certain allergic reactions. It can sometimes be helpful in finding the stage of leukemia or how the body is responding to chemotherapy.

How do you prepare for the test?

In general, you don't need to prepare before having this test. Your doctor may give you some specific instructions.

How is the test done?

A health professional takes a sample of your blood.

How long does the test take?

This test will take a few minutes.

What happens after the test?

  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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