Blood Smear
Reviewed
A blood smear is a test that checks a sample of your blood under a microscope to see whether your blood cells look normal in size, shape, and number.
Preparation and collection
You don't need any special preparation for a blood smear. If your provider has ordered other blood tests, you may need to fast (not eat or drink) for several hours before the test.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- A blood smear alone cannot diagnose a disease. Abnormal results require additional testing and must be interpreted together with your medical history, symptoms, and other tests.
- The quality of the sample and preparation can affect results, but this is managed by laboratory professionals.
What to do next
Your provider will use your blood smear results combined with your medical history, symptoms, and the results of other tests to make a diagnosis. If your results are not normal, your provider may order more tests to help find the cause. Talk with your provider to learn more about your results.