Indwelling umbilical arterial catheter: a preferred sampling site for blood culture.

Indwelling umbilical arterial catheter was evaluated prospectively as an alternative site for blood culture sampling. In 282 infants, 318 paired blood cultures were obtained from the peripheral vein and from the indwelling umbilical arterial line. Duration of umbilical catheter placement ranged from 0.5 to 196 hours; in 17% of the infants, catheters were in place for between 24 and 196 hours. In 13 blood culture pairs the same pathogens were found and had been obtained from the peripheral vein and the umbilical arterial line. Two pairs were positive for discrepant organisms. A total of 11 pairs were positive in one site only, with five positive from peripheral vein only and the other six from the umbilical arterial catheter. However, most of these single-site positive blood cultures were apparently true positives based on supporting laboratory data for infection. Contamination rates were 1.3% and 0.9% for peripheral vein and umbilical arterial catheter blood cultures, respectively. Thus, in sick neonates, the indwelling umbilical arterial line was an alternative and perhaps a preferred site for blood culture sampling.