Contributed Commentary by Erin McCombs
February 23, 2018 | From antibiotic resistance to crunched lab budgets, the challenges in diagnosing infectious diseases are stacking up. Epidemics like the recent Zika virus outbreak show how easily the community can be caught off-guard, while ongoing uncertainty around reimbursement reminds us that many obstacles come from within the healthcare system.
Today's infectious disease tests must do more than ever before: deliver rapid results, detect antibiotic resistance markers, address cost and reimbursement complexities, and allow for the fast development of entirely new assays. Fortunately, the latest diagnostic developments are helping to meet these demands. From multiplex panel tests and flexible pricing, to rapid molecular diagnostics designed to target antibiotic resistance markers, the new generation of infectious disease assays is rising to the challenge.
Antibiotic Resistance & Rapid Results
One of the greatest public health threats we face today, the spread of antibiotic resistance, has significantly weakened our defenses against many infectious diseases, including some long thought to be contained. Drug-resistant infections cost hundreds of thousands of lives each year. Increasingly, the healthcare community is turning to diagnostics to address this crisis, using them in antimicrobial stewardship programs to help reduce transmission of these pathogens.
Diagnostics must not only accurately identify the disease-causing organism — already a tall order for many infections with non-specific symptoms — but they must also detect rapidly evolving markers of resistance. As more and more pathogens become resistant to multiple therapies, being able to use diagnostic results to guide drug choice is critical for patient care.
Conventional culture-based diagnostics are simply not up to the task, taking too long to yield results in a medically actionable time frame. Many clinical performance studies have now demonstrated that nucleic acid-based tests deliver the necessary information faster, reducing the time to establish resistance profiles by as much as two days, and allowing for more informed decisions about treatment for each patient. In most cases, molecular diagnostics are able to identify the disease-causing agent in as little as a couple of hours.
Multiplexing & Reimbursement
For certain situations, there is a real benefit to being able to test for many different pathogens with a single sample from the patient. These panel-based tests are very helpful for cases where non-specific symptoms may suggest a variety of possible causes, and testing each hypothesis serially would delay optimal patient treatment. Panel-based testing is also a good choice for patients in higher-risk groups, such as the immunocompromised or elderly.
However, the advantage of multiplexing is closely tied to a disadvantage of reimbursement: many insurers view multiplex tests more as screening, rather than diagnostic tests, and therefore limit coverage of them. Because of this, it is important for labs to have flexibility in testing. A pathogen-specific test may be the best (and best-covered) choice for an average-risk patient with a fairly straightforward infection, while a broader panel-based test might be the best choice for a transplant patient whose infection defies easy diagnosis.
For the most flexibility, labs can adopt diagnostic platforms that enable masking, a method that allows the lab to use a panel-based test but only select the specific pathogen or pathogens for which to report results. This flexible testing approach can also have flexible pricing, where labs pay only for the results they choose to report. The same test is run for each sample, but results are customized based on what the ordering physician has requested; if all pre-selected results come back negative, more results can be unmasked and viewed without re-running the test. This approach helps clinical labs meet physician and patient needs while keeping costs under control.
IVDs & LDTs
To address emerging infectious diseases such as the Zika virus or a new flu strain, labs must have the tools to develop new assays very quickly. But as more and more labs rely on diagnostic platforms built for specific in vitro diagnostics, the expertise required to design new laboratory-developed tests is not always available when and where it’s needed.
Some platforms now allow medical technologists to run both IVDs and LDTs on the same instrument, both increasing a lab’s flexibility and reducing the time required to design new lab-developed assays. Whenever possible, clinical labs performing high volumes of infectious disease testing should consider these multi-purpose platforms to improve their capacity and test menu options.
What’s Next
The common theme across all of these advances is flexibility. Clinical labs need different options for infectious disease testing based on time of year, patient demographics, reimbursement policies, and volume of demand. The most cost-effective diagnostic platforms will allow for different types of tests — lab-developed and FDA-cleared, single-pathogen and panel tests — while also producing results quickly enough to make a difference for treatment selection. This is an era of changing landscape for infectious disease testing, and labs that can adapt fastest to meet new needs will provide the best results for their communities.
Erin McCombs is Sr. Director of Global Product Marketing for molecular diagnostics at Luminex. She can be contacted at emccombs@luminexcorp.com.