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A comparative study on bacterial cultures of urine samples obtained by clean-void technique versus urethral catheterization.
Acta Paediatr. 2007 Mar; 96(3):432-6.AP

Abstract

Contamination during urine collection causes difficulty in diagnosing infantile urinary tract infection (UTI). Though considered a gold-standard, suprapubic aspiration is traumatic and not always successful. Catheterization and clean void technique were often preferred but their relative usefulness has not been compared.

OBJECTIVES

To compare the culture results of clean void urine (CVU) and catheter urine (CathU) from children below 2-years old known to have no UTI. We tested whether the false-positive rates of CVU were significantly different from that of CathU.

METHODS

Paired CVU and CathU samples were collected from asymptomatic children admitted for micturiting cystourethrogram, and tested for leucocytes and nitrite, and bacterial culture using standard laboratory methods.

RESULTS

Culture results for 98 children (82 boys, 16 girls; aged 6 +/- 4.3 months) were analysed. Analysis by presence/absence of growths showed good agreement between CVU and CathU for boys (Kappa 0.42) but poor for girls (Kappa 0.18). When analysed by colony counts, agreement was poor with CVU yielding more counts than CathU (Kappa 0.1 for boys and 0.04 for girls). If all mixed growth results were considered as contaminants, the false positive rates for CathU and CVU were similar whether the cut-off was defined as 10(3), 10(4) or 10(5)/mL. If mixed growth was believed to cause UTI, CathU produced less false-positive rates than CVU, though both rates were unacceptably high.

CONCLUSION

In uncircumcized boys, both CVU and CathU were prone to contamination. Though the contaminating bacterial counts were lower in CathU culture, the false-positive rates were high with the lower cut-off CFUs. Contrary to previous recommendations, CathU should be interpreted similar to CVU to avoid false positive diagnosis of UTI.

Authors+Show Affiliations

Department of Paediatrics & Adolescent Medicine, Tuen Mun Hospital, Hong Kong.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

17407472

Citation

Lau, Angela Yu, et al. "A Comparative Study On Bacterial Cultures of Urine Samples Obtained By Clean-void Technique Versus Urethral Catheterization." Acta Paediatrica (Oslo, Norway : 1992), vol. 96, no. 3, 2007, pp. 432-6.
Lau AY, Wong SN, Yip KT, et al. A comparative study on bacterial cultures of urine samples obtained by clean-void technique versus urethral catheterization. Acta Paediatr. 2007;96(3):432-6.
Lau, A. Y., Wong, S. N., Yip, K. T., Fong, K. W., Li, S. P., & Que, T. L. (2007). A comparative study on bacterial cultures of urine samples obtained by clean-void technique versus urethral catheterization. Acta Paediatrica (Oslo, Norway : 1992), 96(3), 432-6.
Lau AY, et al. A Comparative Study On Bacterial Cultures of Urine Samples Obtained By Clean-void Technique Versus Urethral Catheterization. Acta Paediatr. 2007;96(3):432-6. PubMed PMID: 17407472.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A comparative study on bacterial cultures of urine samples obtained by clean-void technique versus urethral catheterization. AU - Lau,Angela Yu, AU - Wong,Sik-Nin, AU - Yip,Kam-Tong, AU - Fong,Kwok-Wah, AU - Li,Samantha Po-Siu, AU - Que,Tak-Lun, PY - 2007/4/5/pubmed PY - 2007/5/2/medline PY - 2007/4/5/entrez SP - 432 EP - 6 JF - Acta paediatrica (Oslo, Norway : 1992) JO - Acta Paediatr VL - 96 IS - 3 N2 - UNLABELLED: Contamination during urine collection causes difficulty in diagnosing infantile urinary tract infection (UTI). Though considered a gold-standard, suprapubic aspiration is traumatic and not always successful. Catheterization and clean void technique were often preferred but their relative usefulness has not been compared. OBJECTIVES: To compare the culture results of clean void urine (CVU) and catheter urine (CathU) from children below 2-years old known to have no UTI. We tested whether the false-positive rates of CVU were significantly different from that of CathU. METHODS: Paired CVU and CathU samples were collected from asymptomatic children admitted for micturiting cystourethrogram, and tested for leucocytes and nitrite, and bacterial culture using standard laboratory methods. RESULTS: Culture results for 98 children (82 boys, 16 girls; aged 6 +/- 4.3 months) were analysed. Analysis by presence/absence of growths showed good agreement between CVU and CathU for boys (Kappa 0.42) but poor for girls (Kappa 0.18). When analysed by colony counts, agreement was poor with CVU yielding more counts than CathU (Kappa 0.1 for boys and 0.04 for girls). If all mixed growth results were considered as contaminants, the false positive rates for CathU and CVU were similar whether the cut-off was defined as 10(3), 10(4) or 10(5)/mL. If mixed growth was believed to cause UTI, CathU produced less false-positive rates than CVU, though both rates were unacceptably high. CONCLUSION: In uncircumcized boys, both CVU and CathU were prone to contamination. Though the contaminating bacterial counts were lower in CathU culture, the false-positive rates were high with the lower cut-off CFUs. Contrary to previous recommendations, CathU should be interpreted similar to CVU to avoid false positive diagnosis of UTI. SN - 0803-5253 UR - https://www.unboundmedicine.com/medline/citation/17407472/A_comparative_study_on_bacterial_cultures_of_urine_samples_obtained_by_clean_void_technique_versus_urethral_catheterization_ DB - PRIME DP - Unbound Medicine ER -