Performance of the cobas u 701 Analyzer in Urinary Tract Infection Screening

Autor: Coral Martin, Félix Gutiérrez, Ana Infante, Gregoria Gazquez, Fernando Buñuel, Victoria Ortiz de la Tabla
Rok vydání: 2019
Předmět:
Adult
Male
0301 basic medicine
medicine.medical_specialty
Infection screening
Adolescent
Urinary system
030106 microbiology
Clinical Biochemistry
Screening urine samples
Urine
Sensitivity and Specificity
Gastroenterology
Automation
Leukocyte Count
Young Adult
03 medical and health sciences
Rapid screening test
White blood cell
Internal medicine
medicine
Humans
Prospective Studies
Diagnostic Errors
Urine culture
Colony-forming unit
Microscopy
Urinary tract infection
Automated microscopy analyzer
Bacteria
Receiver operating characteristic
business.industry
Biochemistry (medical)
cobas u 701
General Medicine
Middle Aged
Predictive value
Clinical Microbiology
030104 developmental biology
medicine.anatomical_structure
ROC Curve
Area Under Curve
Urinary Tract Infections
Female
Original Article
business
Zdroj: Annals of Laboratory Medicine
ISSN: 2234-3814
2234-3806
DOI: 10.3343/alm.2019.39.5.464
Popis: Background Negative urine cultures to rule out urinary tract infections (UTI) generate a considerable laboratory workload; thus, a rapid screening test is desirable. We evaluated the performance of a new automated microscopy analyzer, cobas u 701 (Roche Diagnostics International, Rotkreuz, Switzerland) for the screening of UTI, and developed a rule-out strategy to reduce the number of samples requiring culture. We also assessed squamous epithelial cell (SEC) count as a predictor of culture contamination. Methods In total, 1,604 urine samples from outpatients were analyzed with cobas u 701 and culture. Bacterial (BAC) and white blood cell (WBC) counts were used for sample interpretation. To determine a useful cut-off point to predict negative cultures, we selected the highest sensitivity and specificity values obtained from ROC curves. Diagnostic accuracy by age and gender was evaluated. Results Urine culture showed growth of ≥10⁴ colony forming units (CFU)/mL in 256 samples (16.0%). The highest sensitivity (91.8%) and specificity (68.4%) were obtained for cut-off points of 119 BAC/μL and 22 WBC/μL. The combination of BAC and WBC improved the performance of the rule-out strategy with a low rate of false-negative results (1.5%) and a high negative predictive value (NPV, 97.3%). Fifty-seven percent of the samples would not have required culture. SEC count was a poor predictor of culture contamination. Conclusions cobas u 701 can substantially reduce the number of urine samples requiring culture, with a low false-negative rate and a high NPV.
Databáze: OpenAIRE
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