Blood Count Tests
Educational information. Individual clinical review of this presentation by Dr. Ehsan is not yet documented. It does not replace personal medical evaluation.
Source: MedlinePlus, National Library of Medicine. Read the original source
MedlinePlus data edition September 26, 2026. Imported September 27, 2026. These dates do not indicate a new clinical review of the article.
Your blood contains red blood cells (RBC), white blood cells (WBC), and platelets. Blood count tests measure the number and types of cells in your blood. This helps doctors check on your overall health. The tests can also help to diagnose diseases and conditions such as anemia, infections, clotting problems, blood cancers, and immune system disorders.
Specific types include tests for:
- RBC - the numbers, size, and types of RBC in the blood
- WBC - the numbers and types of WBC in the blood
- Platelets - the numbers and size of the platelets
- Hemoglobin - an iron-rich protein in red blood cells that carries oxygen
- Hematocrit - how much space red blood cells take up in your blood
- Reticulocyte count - how many young red blood cells are in your blood
- Mean corpuscular volume (MCV) - the average size of your red blood cells
The complete blood count (CBC) includes most or all of these. The CBC is one of the most common blood tests.
NIH: National Heart, Lung, and Blood Institute
Questions for your care team
General prompts to help prepare for your appointment.
- How does this information apply to my situation?
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- Which tests are useful, and what can they tell us?
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- When is follow-up, and how will we know whether the plan is working?
For a life-threatening emergency, call 911 in the U.S. or your local emergency number.
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