Yield of positive blood cultures in pediatric oncology patients by a new method of blood culture collection

Background. The optimal number of blood cultures and the volume of blood for pediatric blood cultures have not been defined. In 1990 such criteria were established at our institution. We retrospectively reviewed records of all pediatric oncology patients who were admitted for febrile episodes in 1989 and in 1991 and 1992 to determine whether there was an increase in the detection of bacteremia and fungemia. Methods. Blood was drawn via venipuncture and central intravascular catheters and inoculated into the designated blood culture bottles. Each patient had a minimum of two separate blood draws, i.e. two separate cultures; the volume was determined by the patient's weight. In all cases <1% of the patient's blood volume was drawn per culture. Patients' records were reviewed regarding type of malignancy, chemotherapy and neutropenia. Results. The rate of bacteremic patients increased from 12% (13 of 113) in 1989 to 22% (27 of 123) in 1991. This increase continued through 1992 with 23% (27 of 118) of patients having positive blood cultures. Gram-positive bacteria predominated throughout the study period. Conclusions. Although factors such as more aggressive chemotherapy or a different spectrum of malignant diseases may contribute Do the statistically significant increase in identification of bacteremic patients, a standardized method of blood culture collection is merited. The consistent volumes of blood per culture and the minimum of two cultures per febrile episode follow the principles of blood culture collection established for adults. The same principles should apply to pediatric patients.