Clean catch urine collection: Time taken and diagnostic implication. A prospective observational study.

AIM

Clean catch urine (CCU) collection is commonly used in pre-continent children. CCU can be time-consuming and specimens may be contaminated. Our aim was to determine the time taken for CCU attempts and to describe the success of this method in diagnosing or excluding urinary tract infection.

METHODS

Prospective observational study of CCU in pre-continent children aged 2-48 months in the emergency department. Time taken until urine collection, 'successful' (voided and caught), 'missed' (voided not caught) or the procedure 'stopped', were recorded and urine culture results analysed.

RESULTS

Two hundred and seventeen children (131 (60%) male) were enrolled. There were a total of 247 attempts at CCU. For the first attempt, the median collecting time was 30.5 min (interquartile range (IQR) 11-66). Outcome was 'successful' in 64% (95% confidence intervals (CI) 58-70%), 'missed' in 16% (95% CI 11-20%) and 'stopped' in 20% (95% CI 15-26%). Median time if 'successful' was 25 min (IQR 7-46.5), 'missed' 27 min (IQR 11.6-59) and 71 min (IQR 42.5-93) when 'stopped'. One hundred and sixty children had successful CCU collection, 129 were sent for culture. Fifty of 129 (39%) cultures were contaminated. If all urine specimens caught were sent for culture, the estimated yield of an uncontaminated urine specimen was 45%. Contamination was not related to time taken for CCU.

CONCLUSIONS

CCU is time-consuming, frequently unsuccessful and contaminated, resulting in a low overall diagnostic yield. Clinicians could expect a 45% chance of obtaining a definitive urine sample from this method overall.