Blood disorders can cause various symptoms in almost any area of the body. Most commonly, symptoms are caused by decreases in the blood components.
Decreased red blood cells and hemoglobin can cause symptoms of anemia, such as fatigue, weakness, and shortness of breath (see Overview of Anemia).
Decreased white blood cells or immune system proteins can cause recurrent fever and infections (see Fever in Adults).
Decreased platelets or blood clotting factors can cause abnormal bleeding and bruising (see Bruising and Bleeding).