Verification of blood volume for blood culture and detection rate in pediatrics

This study was conducted to estimate the blood culture volume that should be collected from pediatric patients to improve diagnostic abilities.

Blood cultures from neonates and children aged up to 18 years were collected and the volume was measured for over a 1-year period. During the intervention period, examiners were instructed to draw 3 mL of blood for culture, if possible. The pre-intervention period was from June 1 to August 31, 2016. The post-intervention period was from September 1, 2016, to May 30, 2017. The rate of positive detections was calculated and compared between pre and post-intervention periods.

We collected 1352 samples and measured 1327 bottles. During the pre-intervention period, 340 cases were collected with a median blood volume of 1.64 mL; 9 cases (2.7%) were true-positive. During the intervention period, 1012 cases were ordered with a median blood volume of 2.41 mL; 19 cases (1.9%) were true-positive. After intervention, blood volume was increased significantly (p < 0.01). However, there was no significant difference in the rate of positive detections during the study periods (p = 0.254).

In the pediatric clinical setting in a Japanese municipal hospital, the positive detection rate did not improve even when the collected blood volume was increased. One milliliter of blood volume may be adequate for the pediatric bottle in children.