Bagging the bag

Article Outline

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Studies showing the unreliability of bag specimens for making the diagnosis of UTI are plentiful, yet the practice does not seem to die. The current issue of The Journal contains yet another such study, albeit with an interesting twist.

Etoubleau et al in France were able to examine the results of culture of urine from 192 children in whom samples were obtained from both bag and catheter specimens. Not surprisingly, 7.5% of positive cultures obtained from bag specimens were false positive. Intriguingly, 29% of negative cultures of bag specimens were false negatives. The authors speculate on the latter result, suggesting the antimicrobial cleansing regimen which was employed. In any case, in this study, 40% of bag urine specimens yielded either on incorrect or an impossible diagnosis.