For a complete blood count, a member of your health care team takes a sample of blood by inserting a needle into a vein in your arm, usually at the bend in your elbow. The blood sample is sent to a lab for analysis. You can return to your usual activities immediately.

Is CBC test done empty stomach?

When your doctor orders a CBC, there are no special preparations you'll need to take before the test. You are not required to fast (not eat solid foods for 12 hours or so), unless you are having other tests done at the same time that require it.

How do you prepare for a CBC blood test?

Make sure to wear a short-sleeved shirt or a shirt with sleeves that you can easily rollup. You can typically eat and drink normally before a CBC. However, your doctor may require that you fast for a specific amount of time before the test. That's common if the blood sample will be used for additional testing.