All terms in medicine are filled with qualifications and exceptions but, as a broad gauge, these definitions will give you an idea of what is going on. Typically, red cells are round and biconcave. Increases in polychromasia reflects increased marrow production of red cells. These cells are your immune response for such diseases as measles, mumps, colds, etc. They were unjustly believed to be the cause of infectious mononucleosis in the 20's.
Loss of function is seen in lymphomas and lymphocytic leukemia.
This clears up potential confusion about what cells are the problerm and how many do you have. Supposed you saw 90 grans. This may mean you have too many neutrophils or too few lymphocytes. Using the Absolute counts can tell you the answer. Below this, physicians get antsy.