Why it's done

A complete blood count is a common blood test that's done for a variety of reasons:

• To review your overall health. Your doctor may recommend a complete blood count as part of a routine medical examination to monitor your general health and to screen for a variety of disorders, such as anemia or leukemia.
• To diagnose a medical condition. Your doctor may suggest a complete blood count if you're experiencing weakness, fatigue, fever, inflammation, bruising or bleeding. A complete blood count may help diagnose the cause of these signs and symptoms. If your doctor suspects you have an infection, the test can also help confirm that diagnosis.
• To monitor a medical condition. If you've been diagnosed with a blood disorder that affects blood cell counts, your doctor may use complete blood counts to monitor your condition.
• To monitor medical treatment. A complete blood count may be used to monitor your health if you're taking medications that may affect blood cell counts.