Routine blood tests do not confirm a diagnosis of leukemia, but they can be suggestive of possible leukemia. There are three main types of blood cells in a routine blood test, namely white blood cells, red blood cells and platelets. If there is a significant increase or decrease in white blood cells, along with a decrease in hemoglobin and platelets, leukemia is considered a possibility. If all three types of blood cells are completely normal, leukemia is basically not considered. If there are abnormal blood cells and you want to further examine and rule out leukemia, the easiest way is to do peripheral blood cell sorting and if there are primitive or naive cells, basically leukemia should be considered.