hematocrit

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

Your blood is living tissue made up of liquid and solids. The liquid part, called plasma, is made of water, salts and protein. Over half of your blood is plasma. The solid part of your blood contains red blood cells, white blood cells and platelets.

Blood disorders affect one or more parts of the blood and prevent your blood from doing its job. They can be acute or chronic. Many blood disorders are inherited. Other causes include other diseases, side effects of medicines, and a lack of certain nutrients in your diet.

Types of blood disorders include:

• Platelet disorders, excessive clotting, and bleeding problems, which affect how your blood clots
• Anemia, which happens when your blood does not carry enough oxygen to the rest of your body
• Cancers of the blood, such as leukemia and myeloma
• Eosinophilic disorders, which are problems with one type of white blood cell.