How the Beckman Coulter UniCel DxC 880i integrated chemistry and immunoasssay platform stands up to rigorous laboratory testing
Thomas Rieger Dr med Laboratory Director
Institute for Laboratory Medicine and Clinical Microbiology “Evangelisches” Hospital Oberhausen, Germany
The changes to the diagnostic service offered by the Institute for Laboratory Medicine and Clinical Microbiology at the “Evangelisches” Hospital reflect those taking place throughout Europe.
An increasing number of hospitals are concentrating their laboratory testing in one place, separating their resources between specialist analytics and the core laboratory. For this to be successful, a newly centralised lab must have sufficient overall capacity to handle the additional workload from the whole group. The emerging technology of egrating chemistry and immunoassay testing on a single platform, often referred to as an integrated workstation or workcell, can provide the solution. This was the reason why, in autumn 2007, our laboratory became the first in the world to install and evaluate the UniCel DxC 880i.
Oberhausen is a 580-bed university hospital, and the lab now serves five external hospitals that have taken the decision to consolidate all immunoassay testing in our lab. We perform more than 600,000 clinical chemistry tests a year and, crucially, handle a high proportion of emergency testing demands from the hospitals in our network. We currently analyse 600 tubes a day, running an average of 12.5 tests per tube. Around 3% of these tubes are required for additional testing.
The decision to install an integrated system was taken in stages. First, we carried out a recent workflow analysis focusing on the key areas of preanalytics, testing requests, storage, transport and maintenance (Figure 1). This showed that the lab was actually spending only 15% of its working day on the actual testing, with 65% of its time taken up by the preanalytics – aliquoting and other manual processes. For some samples, up to three aliquots needed to be taken to handle all the immunoassay test requests, a process that held up our overall turnaround time results.
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Demand for consistently high throughput
In addition, we assessed the ability of our existing standalone systems to handle both current and projected workloads, and it was clear from the assessment that their performance was contributing to the delay. For instance, our existing clinical chemistry system was taking far too long – around 108 minutes to run 90% of the tests. Overall, the analysis showed that we needed to:
- Improve throughput substantially by analysing a far higher number of samples in a faster time slot.
- Reduce manual processing time, particularly the high requirement for aliquoting.
- Improve our STAT and routine handling. Offer clinicians a more comprehensive testing menu.
- Make best use of our existing and future limited staff resources.
We made improving throughput a first priority and decided to upgrade our analysers immediately, taking this into account. The challenge was that they would have to deliver quantifiable improvements while running initially as standalone systems, but be capable of upgrading to an integrated system with the minimum of disruption – and without any major reduction to throughput. We drew up requirements for the specific, and higher, throughput levels needed to deliver to satisfy current and future testing demands. Finally, we selected a clinical chemistry system capable of running up to 1,440 tests per hour and, crucially for our expanded immunoassay testing service, an analyser able to run up to 400 tests per hour – but also with an extensive menu (Beckman Coulter’s UniCel DxC 800 clinical chemistry system and the company’s DxI 800 immunoassay analyser). We knew that by installing an additional module, the UniCel Closed Tube Aliquoter (UCTA), we could easily upgrade both these analysers to provide the lab with a high-throughput integrated system.
Immunoassay turnaround time down one-third
Our next workflow analysis showed that the two new analysers (DxC 800 and DxI 800) running in parallel and, before being integrated, had made an immediate improvement to turnaround time (TAT). What was most significant was that by placing such an emphasis on consistently high throughput from our standalone systems we had already been able to reduce clinical chemistry testing processing time by approximately two-thirds and immunoassay by one-third. The total run time of both analysers (in parallel) was 127 min 47 s, with a manual preparation time of 35 min. This gave a throughput time of 162 min 47 s. But this meant that the DxI was now delivering 90% of our test results within 49 minutes, and the DxC in 35 minutes over the time period (compared with the 108 minutes on the previous system to run the same tests) (Figures 2 and 3).
We therefore felt confident in upgrading to the integrated platform and did so by installing the UCTA module. This modular unit fits between the DxC and DxI systems, linking them into one integrated platform and providing a single entry point for samples. At the same time it extended the company’s unique closed-tube technology, already available in its clinical chemistry systems, to immunoassay testing. Most importantly, taking 140 routine tests, we compared our already improved performance using the highthroughput analysers in parallel and quantified the differences made by configuring them into an integrated workcell, the UniCel DxC 880i.
We found that by using the UniCel DxC 880i system we were able to deliver even greater improvements to overall TAT – achieving an additional reduction of almost 20%, to 131 min 26 s from 162 min 47 s (Table 1). Because the samples are processed via the UCTA there is no additional preparation time on the UniCel DxC 880i. Instead, this takes only a few additional minutes rather than the 35 minutes previously required – so there is no significant slowdown to the workflow. This has a significant impact on the total TAT (Table 2).
Reagent loading – while the system runs
In addition, having an integrated system means we can now call upon a menu of more than 150 tests for both chemistry and immunoassay – with 120 onboard. The UniCel DxC 880i also gives us the option to load and unload reagents while the system is running, or “on the fly”, without staff wasting valuable time shutting the system down.
We have been able to remove delays caused by the lab’s high reliance on staff having to aliquot samples, as well as automating 90% of other manual processes. Bottlenecks are reduced, and we can use one tube without needing to decap and divide the sample, saving time and removing the risk of error or sample contamination. For example, with the UniCel DxC 880i we are able to run troponin I in tandem with any chemistry tests required without having to switch them to a separate system.
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Staff benefit from enhanced working environment
We also find closed-tube aliquoting provides added protection for our staff, particularly when they are working under pressure from the emergency departments to run additional or STAT tests. Indeed, the move towards an integrated system has delivered many benefits for our staff, enabling us to make better use of this valuable but limited resource. We have been able to redeploy some technicians to carry out essential quality control procedures.
In addition, our team is better able to focus on the specialist type of immunoassay testing for which we have always been highly regarded – and that will always require manual involvement.
To confirm the benefits, we carried out a further evaluation of the UniCel DxC 880i’s performance, across routine and STAT tests, to ensure that it consistently delivered the efficiencies we had observed. We also checked for carryover, something that is particularly relevant for sensitive assays, by running Beta hCG (approx. 17,000 U/ml), ferritin (approx. 4,500 ng/ml), PSA (approx. 700 ìg/l) and HBS Ag, in different scenarios. But no carryover could be detected − whether loading the samples via the UCTA, loading directly onto the immunoassay side of the system or requesting an additional test when the sample has been already processed on the chemistry side of the UniCel DxC 880i.
We also tested the Infectious Disease and Blood Virus panel on the UniCel DxC 880i. The overall concordance to another automated system was demonstrated.
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The immediate benefits of integrated, automated laboratory systems, capable of maintaining the high throughput of component units, are significant. The lab delivers improved efficiency with consistent results, while handling highvolume workloads and maintaining health and safety standards. There is also a significant impact on patient care, as laboratory staff gain more time to focus on the information and analysis the system provides clinicians, adding value to the overall diagnostic service.
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