What percentage of children with haematogenous osteomyelitis will have abnormal lab studies?

We had an interesting case in our practice which led to the following two questions. The answers are from UpToDate : What percentage of children with haematogenous osteomyelitis will have abnormal lab studies? LABORATORY FINDINGS — Elevations in peripheral white blood cell count (WBC) are variable and nonspecific, while elevations in the erythrocyte sedimentation rate (ESR), and