The Gran # on lab results refers to the granulocyte reading. This basically falls under the white blood count, or the WBC, which is divided into the Gran and the LYM, or Lymphocyte, figures.
The immune system functions with the help of white blood cells and when an infection occurs within the body, these soldiers are called to fight against the intruders.
The aim of obtaining the Gran count is to determine whether there is an elevated number of these cells within the body.
When the Gran count is high, this indicates that there is an infection in the body. When a viral infection is present, this could end up lowering the lymphocyte levels.
If you are reading your own test results and you want to know what they mean, it is best you contact your doctor.