Comparison of screening methods

According to ECDC (Magiorakos et al, 2017), there has been no consensus reached on the optimal microbiological method for the detection of CRE carriage. However, it is ad-vised that the chosen method should be highly sensitive and provide results in a timely manner to guide the proper implementation of infection control and prevention (ICP) measures. The choice of the screening method is usually dictated by the local needs, created ICP protocols, financial and structural abilities as well as therapeutic traditions in the country or region. Interestingly, despite development of novel diagnostic methods, many laboratories still rely on traditional diagnostic methods as the main method for screening of carbapenem resistance (Kostyanev et al., 2019) as traditional diagnostic is relatively reliable, highly sensitive and, most of all, low-priced.

As it has been noted earlier, the main difference between the traditional screening method and the case company’s screening solution is time-to-result. However, many aspects vary between these methods, which can directly impact the work in laboratories.

While the price per test using the case company’s solution appears higher than if the traditional method is used, the wider understood cost-effectiveness should make the change to the case company’s solution interesting also from the laboratory point of view.

Figure 44 compares the process of performing a test for CRE using the traditional and case company’s molecular method. The figure is constructed by the researcher based on two days of observations of the laboratory processes and existing materials gathered from the case company and scholar publications (e.g., Ambretti et al., 2019).

Traditional screening (top) and screening using the case company’s solution (bottom).

CRE screening process using traditional methodCRE screening process using case companys molecular solution HospLaboratoryHospitalLaboratory

Sample

Figure 44 shows the traditional screening process at the top of the page and the screen-ing process usscreen-ing the case company’s solution is presented in the graph at the bottom of the page. Both processes are presented in a more general way as each of the steps included in the graphs can be broken down into subprocesses needed to perform the entire step. However, even these simplified graphs show that the number of steps fol-lowing the traditional method is far larger as compared to the case company’s solution.

The steps from sample collection to sample pre-processing are the same for both meth-ods. These steps may last anything between 0.5 hour and 3 hours, depending on the hospital-laboratory logistics and laboratory internal protocol.

The later steps in the screening process differ between both methods. As it comes to traditional methods, the first step in sample processing is sample cultivation. Sample cultivation, also called bacteria culturing, is a method that requires following several sub-steps that enable the growth of microbial organisms, which is necessary for further char-acterization of the bacteria. Then, the plate is carefully closed and moved to the incuba-tion place where it stays for 16 to 24 hours for the bacteria to grow. After the incubaincuba-tion period, the laboratory technician examines the plate. If there is any trace of bacteria found, the laboratory technician sends a message to the hospital system about a poten-tially positive result. Then, the staff performs additional tests to confirm the type of bac-teria, and within the next 1-24 hours, the final result would be reported. In that case, the hospital gets the final result within 18-44 hours from sample collection.

In the case there is no bacteria growth visible after the first incubation period, the plate is incubated for the next 16-24 hours, and after that time, the plate is examined again. In case there are any bacteria visible, the same protocol as described earlier is followed, and the final result is provided to the hospital 48-76 hours from sample collection. If there is no bacteria visible after the second incubation period, the result is reported as nega-tive, and no additional sample testing is done. Usually if the patient is the CRE carrier, the bacteria growth would be visible after the first incubation period, and hence hospitals get preliminary positive results within 24 hours. However, the negative result cannot be preliminary stated and, consequently, the negative result is only reported after 48 hours.

On the other hand, when the case company’s solution is used, a laboratory technician pre-processes the sample and inserts it into the case company’s instrument that per-forms the entire analysis and automatically sends results to the hospital information sys-tem. The analysis using the case company’s solution takes just over an hour and multiple samples can be analyzed at the same time. As Figure 44 presents, both positive and negative results are delivered to hospital wards within the same timeframe of 2-4 hours from the sample collection. Moreover, when the case company’s solution is used, there

can be different types of tests run in the same instrument at the same time, which addi-tionally enhances workflow in a laboratory.

While in the case of the traditional method most of these steps require the laboratory staff’s active involvement, the analysis of the sample and reporting is automated by the case company’s solution and requires a minimum commitment of the laboratory staff.

Hence, the laboratory technician’s hands-on-time needed to analyses CRE samples is much shorter when the case company’s screening solution is used. Also, the lower num-ber of steps poses smaller chances for human-related errors and potential sample con-tamination, which could influence the outcomes of the analysis.

Then, traditional analysis requires many different accessories and materials to run the screening. Although the cost of these accessories and materials is not substantial, the laboratory must make sure that all these elements are available at all times. In contrast, to run the test with the case company’s solution, only the test kit and a pipette are needed, which is much easier to keep track of. Furthermore, while the accuracy of the traditional method is on a relatively high level and oscillates between 80-90%, the accu-racy of the screening result with the case company’s solution is close to 100%. The higher the accuracy of a method, the more reliable results are provided to hospitals.

As presented in this section, the use of the case company’s solution to screen patients

‘at-risk’ of CRE carriage does not only allow for bringing positive and negative results earlier but also simplifies the workflow in the laboratory. The molecular solution enables the provision of more accurate results to hospitals and lowers the extent of manual work performed by laboratory technicians. Whereas it may seem that direct costs of traditional screening are much lower as compared to molecular screening, a broader perspective on costs and benefits of screening should be considered. Therefore, the efficiencies in the laboratories should be accounted for as well as the potential differences in costs and benefits for hospitals if the case company’s molecular solution replaces the traditional screening method in a laboratory.

5.3 Towards a customizable value proposition