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Background: To implement Lean Six Sigma in our central laboratory we conducted a project to measure single pre-analytical steps influencing turnaround time (TAT) of emergency department (ED) serum samples. The traditional approach of extracting data from the Laboratory Information System (LIS) for a retrospective calculation of a mean TAT is not suitable. Therefore, we used radiofrequency identification (RFID) chips for real time tracking of individual samples at any pre-analytical step.
Methods: 1,200 serum tubes were labelled with RFID chips and were provided to the emergency department. 3 RFID receivers were installed in the laboratory: at the outlet of the pneumatic tube system, at the centrifuge, and in the analyser area. In addition, time stamps of sample entry at the automated sample distributor and communication of results from the analyser were collected from LIS.
Results: 1,023 labelled serum tubes arrived at our laboratory. 899 RFID tags were used for TAT calculation. The following transfer times were determined (median / 95th percentile in min:sec): pneumatic tube system → centrifuge (01:25 / 04:48), centrifuge → sample distributor (14:06 / 25:33), sample distributor → analysis system zone (02:39 / 15:07), analysis system zone → result communication (12:42 / 22:21). Total TAT was calculated at 33:19 / 57:40 min:sec. Manual processes around centrifugation were identified as a major part of TAT with 44 % / 60 % (median / 95th percentile).
Conclusions: RFID is a robust, easy to use, and error-free technology and not susceptible to interferences in the laboratory environment. With this study design we were able to measure significant variations in a single manual sample transfer process. We showed that TAT is mainly influenced by manual steps around the centrifugation process and we concluded that centrifugation should be integrated in solutions for total laboratory automation.
DOI: Clin. Lab. 2011;57:75-81
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