Having a low blood count means that a person's bone marrow is not making enough of one or more types of blood cells, according to the Aplastic, Anemia & MDS International Foundation. The medical term for a low blood count is cytopenia.
Doctors use a blood test called a complete blood count to measure how many of each blood cell type is in a blood sample. Red blood cells, white blood cells and platelets are the different types of blood cells. If any of these are low, a blood smear can determine if the cells are abnormal, as reported by AAMDS. Low blood counts are caused by conditions such as vitamin deficiencies and bone marrow failure diseases. People who have low blood counts may need other tests performed, such as examinations of bone marrow samples.
The term for a low red blood cell count is anemia. Symptoms of anemia can include tiredness, loss of appetite, paleness and trouble breathing. A low white blood cell count is known as neutropenia. People with neutropenia often have repeated fevers and infections, difficulty breathing and mouth sores. A low platelet count is called thrombocytopenia, and sufferers may have bruising and excessive bleeding, explains AAMDS.