In order to determine the diagnostic usefulness of culturing the subcutaneous catheter segment, an analysis was performed using data derived from two prospective, randomized studies that included 479 patients with central venous catheters and 13 episodes of catheter-related bacteremia. The results indicate that quantitative culture, using the roll-plate and sonication methods, of the subcutaneous catheter segment did not add to the diagnostic yield (sensitivity, 83-100%; specificity, 82-97%; negative predictive value, 100%) of semiquantitative and quantitative catheter-tip cultures or aid in identifying catheter-related bloodstream infections.