KEEPING TRACK OF THEIR CHILD’S BLOOD cell counts becomes a way of life for parents of children with solid tumors. Unfortunately, misunderstandings about the implications of certain changes in blood values can cause unnecessary worry and fear. To help prevent these concerns, and to better enable parents to spot trends in the blood cell values of their child, this appendix explains the blood cell counts of healthy children, the blood cell counts of children being treated for solid tumors, and what each blood cell count value means. It also briefly describes other blood tests commonly needed in children with solid tumors.