Blood Disorders are generally categorized by physicians according to the nature of the complaint. There are disorders of blood production, disorders within the blood cells, infections in the blood, and disorders of the blood clotting mechanism.
The following table lists the most common disorders that are caused by blood disease or malfunction and their basic characteristics.

List of blood disorders  (most common)

Agranulocytosis   

- Reduced production of white blood cells

Anemia   

- Reduced production or loss of red blood cells

Blood poisoning   

- Infection of blood stream by bacteria

Christmas disease   

- Defective blood clotting

Hemophilia   

- Defective blood clotting

Leukemia   

- Uncontrolled and disorderly increase of white blood cells

Malaria   

- Parasitic infestation of red blood cells

Mononucleosis   

- Excess of large white blood cells

Myeloma   

- Cancer of the bone marrow

Polycythemia   

- Excessive production of red blood cells

Purpura   

-Bleeding under the skin

Sickle cell anemia   

- Deformity of red blood cells in which the cells take on a sickle shape

Thalassemia   

- Deformity of red blood cells

Thrombocytopenia   

- Decreased number of blood platelets

Of the conditions listed, most are serious and require immediate medical treatment. However, many characteristics cited here may also be indicative of some other clinical disorder.
An accurate medical history and physical examination by a physician are essential for adequate diagnosis of a problem.