Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology

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Indexed in KCI, KoreaMed, Synapse, DOAJ
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pISSN 2288-0585 eISSN 2288-6850

Factors Influencing the False Positive Signals of Continuous Monitoring Blood Culture System

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2014 June, Volume 17, Issue 2, pages 58-64.

https://doi.org/10.5145/ACM.2014.17.2.58

Factors Influencing the False Positive Signals of Continuous Monitoring Blood Culture System

Young Uh1,2, In Ho Jang1, Soon Deok Park1, Kab Seung Kim1, Dong Min Seo2, Kap Jun Yoon1, Hee Kyoung Choi3, Young Keun Kim3, Hyo Youl Kim3
Departments of 1Laboratory Medicine, 2Medical Information Development and 3Internal Medicine, Yonsei University Wonju Severance Christian Hospital, Wonju, Korea

Abstract

Background: The false positive signals of a continuous monitoring blood culture system (CMBCS) increase the reporting time and laboratory cost. This study aimed to determine the highly relevant variables that discriminate false positive signals from true positive signals in a CMBCS.

Methods: Among 184,363 blood culture sets (aerobic and anaerobic), the signal-positive samples according to a BACTEC FX system (Plus Aerobic/F, BDA; Plus Anaerobic/F, BDN) and BacT/Alert 3D system (Standard Aerobic, BSA; Standard Anaerobic, BSN) between April 2010 and November 2013 were classified into two groups: false positive or true positive signals. The data of 15 parameters between the two groups were then statistically compared.

Results: Among total blood cultures, the positive rates of CMBCS signals according to BDA, BDN, BSA, and BSN were 4.9%, 2.8%, 3.8%, and 3.2%, respectively. The false positive rates of CMBCS signals according to BDA, BDN, BSA, and BSN were 0.6%, 0.1%, 0.1%, and 0.1%, respectively. The blood volume, detection time, time interval between admission and test, C-reactive protein concentration, leukocyte count, delta neutrophil index, and mean peroxidase index showed statistically significant differences between the two groups.

Conclusion: There were no variables with diagnostic sensitivity and specificity for discriminating the two groups. Therefore, analysis of bacterial growth curves produced by CMBCS is needed for early and effective detection of false positive signals. (Ann Clin Microbiol 2014;17:58-64)

Keywords

Blood, Culture, False positive, Monitoring, Signal