3 year old with high WBC and platelets?!?!

She has had high WBC and platelets for over a month now....the doctor is going to give her a urine test and if they can't find anything they are going to refer her to a hemotologist......She has had abosolutley no symptoms of anything....no fever, no swollen lymph nodes, no lack of energy or appetite. I am worried it could be childhood leukemia...what else could it be???? Why else would they send her to a hemotologist??? I am very worried and scared to death it is cancer:(. Has anyone been through this before or have any info they can share....I would really appreciate it!!!