Table 2.

Criteria for the Diagnosis of UTI53

Method of CollectionColony Count (Pure Culture)Probability of Infection (%)
SPAGram-negative bacilli: any number>99%
Gram-positive cocci: more than a few thousand
Transurethral catheterization>105 95%; Infection likely suspicious; repeat infection unlikely
104–105
103–104
<103
Clean void
 Boy>104 Infection likely
 Girl3 Specimens ≥105 95%
2 Specimens ≥105 90%
1 Specimen ≥105 80%
5 × 104 − 105 Suspicious, repeat
104 − 5 × 104 Symptomatic: suspicious, repeat
Asymptomatic: infection unlikely
<104  infection unlikely