With rapid evolution in the molecular platforms available for clinical testing, it can be challenging for lab managers to select the best option for their needs. Recently, one of the primary differences that has emerged in molecular platforms is open systems versus closed systems.

A closed system is often described as “sample to answer” or “sample to result.” These systems require minimal hands-on time because all processes needed to generate a test result — including most sample prep steps — are performed automatically within the platform without the need for human intervention. Closed systems incorporate thermal cycling, quality control, and full protocols to generate a clinical result.

An open system, by contrast, involves multiple instruments and workflows. In this approach, laboratory staff move samples and plates around, add reagents as needed, and employ a workflow that may include both automated and manual steps.

Neither option is right for all labs and all types of tests. So how do you choose between them? Let’s review several factors to consider in your decision-making process.

Capacity

One of the most important factors is throughput. For tests that labs rarely run, or for low-volume labs, an open testing platform is often sufficient. In these cases, there is little need to have a full system dedicated to a certain test or fixed menu of tests.

But for tests that are being run often, with many samples processed together, a closed-end system can be the better choice. These platforms are designed to be lab workhorses, capable of analysing dozens or hundreds of samples at once without requiring additional hands-on time from limited staff resources.

The COVID-19 pandemic has provided an excellent demonstration of this concept. For labs processing just a handful of samples per week, demand could be met with even the most manual workflows. But in laboratories that had to implement high-capacity testing to generate results from thousands of samples per week or even per day, closed systems provided the necessary throughput without overtaxing the staff.

Flexibility

When it comes to molecular testing, does your lab offer a broad test menu, or do you tend to run the same few tests all the time? The level of flexibility you need is another key factor in the choice of open or closed systems.

Typically, closed platforms are designed for either a single test or a small number of tests that all perform well in the same type of automated system. If your laboratory runs a lot of, say, oncology panel tests, then a closed system focused entirely on oncology analysis could be an excellent choice. Having a single automated system take care of a large proportion of the tests run in a laboratory frees up valuable resources for other higher-value medical tasks.

In addition, closed systems can be conducive to running highly regulated in vitro diagnostics. For clinical labs, they can be helpful for minimising the validation processes and registration challenges needed to get a new IVD routine test up and running.

But if your laboratory needs a high level of flexibility in testing, then a closed system is likely not the ideal choice. Open systems enable a much broader range of testing options and are a good match for laboratories that run many different tests from various vendors on a smaller number of samples each day, or often add new tests to their menu.

In addition, laboratory-developed tests require an open system. In labs that frequently run tests they have developed and validated internally, closed systems typically do not provide the flexibility needed to support such workflows.

Resources

While open systems are good for flexibility, they tend to require more resources — both in cost and in staff time. Open platforms need far more optimisation to implement, in part because they incorporate reagents and instruments from a number of different vendors. They also involve more experimental work, often in time-consuming manual steps.

During the COVID-19 pandemic, many lab teams discovered that they could produce more results with greater efficiency and at lower cost by using closed systems. An automated approach with true walkaway functionality contributes to lower costs by minimising sample prep, freeing up staff to perform other tasks, and running more samples at a time. Closed systems also require less setup and training and are significantly easier to operate than open systems.

In addition, closed systems were less affected by supply constraints during the pandemic because all reagents and consumables came from a single vendor, whereas open systems are more vulnerable to supply chain issues because an entire testing procedure can become inoperable when a single type of pipet tip, sample plate, or buffer solution becomes unavailable.

For lab teams planning to purchase an automated system, it would be ideal to start by identifying which tests need to be automated, determining anticipated test volumes, and assessing the availability of expertise and resources needed to optimise tests in order to determine whether an open or closed system would be more beneficial for your current lab setup .