Analysis of the comparative work-flow and accuracy of the VITEK®2 Compact and the ATB Expression® system

Abstract number: 1134_01_310

Blanc V., Brugel P., Lerousseau L., Mourier M.C., Blandin A., Raynaud M.F.


The aim of this study was to analyse the impact of introducing into our routine microbiology laboratory the VITEK®2 Compact (V2C), bioMérieux France, a new automated identification (ID) and susceptibility testing system (AST). Primary focus was to measure potential gains in laboratory productivity and operating costs. Secondary focus was to evaluate the quality of ID/AST results analysed by the system test validation softwares.


The evaluation took place in our 532-bed hospital from Sept to Oct 2004. 400 routine isolates, except fastidious bacteria: 57% Gram-negative, 40% Gram-positive and 3% yeasts were tested using our in-house method, ATB Expression (ATBEx) in parallel with the V2C. This represented 91% of laboratory activity, from 370 various clinical samples. Data were collected on 4 parameters:


Independent analysis and chronometric time measurement of the general work process: from specimen reception, ID/AST set-up to result validation.


The total ID/AST cost including technician time (cost per hour) was calculated.

ID Accuracy:  

Tests were performed in parallel and discordant results were tested by molecular technique.

AST Confidence:  

Comparison was made of ATBEx Expert software and V2C Advanced Expert SystemTM (AES) for result agreement. The Medical microbiologist expertise provided final results on any discordant results.


The global process time gain with the V2C was 12 hrs due to a) the more rapid ID/AST result reporting time (mean detection of 6 hrs for V2C and 18 hrs for ATBEx), b) the faster manipulation time (1.5 min vs 5.5 min), c) the faster AES validation. The overall operating cost was reduced by 15% with V2C.The overall ID agreement between the systems was 94%. Global agreement with AST expertise was more than 95% with both systems.


We underline the benefits of the V2C in the setting of a medium sized microbiology laboratory. V2C compared well to our robust ATBEx overnight method and provided time and cost gains. The V2C AES validation tool allowed technicians to perform first level ID/AST validation confidently before biologist final approval. Further investigations are planned to study clinical impact of rapid ID/AST reporting with this innovative instrument in a unit of our hospital.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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