A blood count is a test performed to count the different types of blood cells.
There are three types of blood cells - red cells that contain hemoglobin and carry oxygen, white cells that fight infections and platelets that help in blood clotting.
A blood count measures hemoglobin, counts the different types of white blood cells and platelets.
Cancer or its treatments (like chemotherapy and radiation) can result in a fall of any or all of these components. This can be bad for the body if they fall too low. It often becomes necessary to check the blood count at diagnosis and periodically during treatment to make sure that the counts are not below a certain level.
If the blood count is abnormal, it may become necessary to infuse blood or platelets or use growth factors to increase the levels to normal. Treatment may have to be delayed or modified as well.