Preoperative laboratory testing of children undergoing elective surgery.

The routine preoperative evaluation of pediatric patients often includes a history, physical examination, complete blood count, and urinalysis (UA). We retrospectively reviewed the records of 486 elective surgeries in children to determine the role of abnormal preoperative laboratory test results in perioperative management. Anemia or microcytosis was apparent in 17% of patients, and abnormal UA results were found in 15%. More than 80% of the abnormal UA results were historically known, clinically insignificant, or false-positives. Only five children had surgery canceled owing to abnormal laboratory tests: two owing to anemia, two to an abnormal UA, and one because of a prolonged partial thromboplastin time. Both children with anemia were treated with iron and subsequently underwent surgery without complication. Of the abnormal UAs, one was contaminated, and the cancellation of surgery resulted in a complication requiring emergency surgery. The other abnormal UA was a probable asymptomatic bacteriuria, and the infant later underwent surgery uneventfully. These data suggest that a routine UA adds little to the preoperative evaluation of a healthy child, and should be omitted.