Positive Urine Cultures: Do I Hear Ten to the Sixth?

Changing the definition of a positive voided urine culture from ≥10exp5 to ≥10exp6 cfu/mL reduces false-positive results without sacrificing sensitivity.

Laboratory diagnosis of urinary tract infection (UTI) using standard culture techniques is usually defined as a urine culture of ≥10exp5 colony-forming units per mL (cfu/mL), but serial dilution of urine samples before culturing allows detection of UTIs at higher concentrations. To examine the optimal urinary bacterial concentration for diagnosing UTI, investigators in the U.K. tested paired urine samples after serial dilution from 203 children (age range, 2 weeks to 17 years) with suspected UTI. All urine samples were voided; samples from infants were collected in sterile pads.

Among the first urine samples, 90 were sterile (<10exp3 cfu/mL), 21 grew <10exp5 cfu/mL of a single uropathogen, 48 grew ≥10exp5 cfu/mL of a single uropathogen (UTI …

Reviewing Authors

Cornelius W. Van Niel, MD

Disclosures

EquityMedtronic; Express Scripts; Johnson & Johnson; Merck

Cornelius W. Van Niel, MD

Disclosures

EquityMedtronic; Express Scripts; Johnson & Johnson; Merck

Sarah Bergman Lewis, MD

Positive Urine Cultures: Do I Hear Ten to the Sixth?

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Reviewing Authors