A complete blood count (CBC) is a blood test used to evaluate your overall health and detect a wide range of disorders, including anemia, infection and leukemia.
A complete blood count test measures several components and features of your blood, including:
- Red blood cells, which carry oxygen
- White blood cells, which fight infection
- Hemoglobin, the oxygen-carrying protein in red blood cells
- Hematocrit, the proportion of red blood cells to the fluid component, or plasma, in your blood
- Platelets, which help with blood clotting
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.
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The following are normal complete blood count results for adults:Red blood cell count
Male: 4.35-5.65 trillion cells/L*
(4.35-5.65 million cells/mcL**)
Female: 3.92-5.13 trillion cells/L
(3.92-5.13 million cells/mcL)Hemoglobin
Male: 13.2-16.6 grams/dL***
Female: 11.6-15 grams/dL
Male: 38.3-48.6 percent
Female: 35.5-44.9 percentWhite blood cell count
3.4-9.6 billion cells/L
(3,400 to 9,600 cells/mcL)Platelet count
Male: 135-317 billion/L
(135,000 to 317,000/mcL)
Female: 157-371 billion/L
(157,000 to 371,000/mcL)
- * L = liter
- ** mcL = microliter
- *** dL = deciliter