External Quality Assessment for Bacterial Identification: A 4-Year Multicentre Implementation Study

G. Morabito, C. Di Rosa, C. Lacava - Oneworld Accuracy Italia srl (1WA)

Aim of the Study

The accurate identification of bacterial species isolated from different biological sources (blood, urine, sputum, swab and wound) is of pivotal importance in the diagnosis and management of bacterial infections and, consequently, in preventing increased morbidity and healthcare costs. Regular participation in External Quality Assessment (EQA) programs plays an essential role in ensuring accurate bacterial identification through monitoring aimed at improving labs’ performance.  The aim of this study was to analyze the results collected for Bacterial Identification EQA in a systematic manner and based on a yearly schedule (test events) and to identify potential benefits of participation in an EQA program as well as the common issues encountered by the participants.



The EQA program for Bacterial Identification was designed and implemented by Oneworld Accuracy to test laboratories’ proficiency. This study’s focus was on 8 EQA test events that were conducted between 2014 – 2017 across Italian laboratories. In each EQA test event, five samples consisting of inoculated loops or KWIK-STIK™ Ampoule/Swab of various matrixes including blood, urine, sputum, swab, wound were provided to labs. Samples were challenged using both manual and automated methods from Becton Dickinson, Biomerieux, Liofilchem and Siemens. Data collected over the 4 years of EQA test events have been analyzed and segregated based on the evaluation’s outcome (graded as Acceptable or Unacceptable). Samples have then been grouped according to source material and compared amongst each other. The established criterion was the identification of bacteria at the species’ level. Labs that identified the bacterial species were thus employed to establish the overall performance.



A total of 110 laboratories, with participation to all 8 EQA test events, were included in this study. Although participation rate varied based on sample matrices, the average participation rate was 84% across the study. Overall, laboratories demonstrated good proficiency in identifying bacteria at the species’ level in urine, sputum, swab and wound with high accuracy. Lower accuracy was shown when identifying bacteria from blood matrices and in cases when anaerobic cultures were required.

Other issues encountered by laboratories, preventing them from meeting the study’s criterion, included sample contamination, misidentification, wrong culture media employed, missed correlation between source material and clinical history.



Our data show that systematic participation to EQA schemes can be instrumental to improve labs’ performance and detection of common issues so that corrective actions can be promptly identified and taken in a timely manner to restore high quality services.

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