Thursday, June 01, 2023

by Brian K. DuChateau, Ph.D., D(ABMLI)

The need for increased access to immediate diagnostics and care has never been highlighted more than during the pandemic. And one by-product of the pandemic has been the rapid implementation and adoption of innovative testing technologies. These instant health care delivery tools, including next-generation rapid antigen tests have transformed the way we can deliver health care at the point of need, whether that be in hospitals, labs and importantly in community-based settings. The forthcoming generation of rapid antigen tests leverage novel technologies to allow both speed and accuracy at the nexus of action or the point of need where critical split-second medical decisions are made.

The latest point of care testing technologies not only promise accurate and fast results but also serve as a key component in addressing testing access and inequities. The Lancet study released earlier this year “The silent and dangerous inequity around access to COVID-19 testing” explained that POC rapid antigen tests are one of the most promising tools to increase access to testing and address the extreme inequities the pandemic exposed in testing across low- and middle-income countries (LMICs).

And, while rapid diagnostics provide an effective and scalable care delivery model at the point of need, they are also crucial for controlling future infectious outbreaks. Bill Gates, in his recent book, “How to Prevent the Next Pandemic” presents a detailed strategy on what can be done at a global scale to avoid the catastrophic impact of another pandemic. His recommended framework for pandemic prevention and response coordination specifically calls out point of care diagnostics as having untapped potential, which we can apply to disease outbreaks.

If we are to future proof our health system today, we must ensure diagnostic equity—integrating point of care diagnostics into every part of our health system—hospitals, labs, and also pharmacies, schools, and other community settings.

Laboratory-run PCR tests are expensive, required skilled labor to perform and do not guarantee this level of efficiency, especially for care centers in remote communities. Laboratory tests may take days to run, and the facilities are often miles away from community hospitals, not an enabling ecosystem for treatment follow through for people that travel long distances. Additionally, rapid antigen tests also circumvent the “persistent positive” results common to PCR tests, which indicate an infection for an extended period even when the person is likely no longer contagious. Antigen tests offer an advantageous alternative, since a growing body of evidence demonstrate that antigen tests correlate more closely to culture suggesting positive results are more likely to be from active infections. In a study from a group at Johns Hopkins University (Pekosz et. al.), antigen tests demonstrated a higher positive predictive value (90%) than rt-PCR (70%) when compared to culture-positive results. Similar findings were reported by a group at Harvard (Kirby et. al), however their study design went a step further to include both lateral flow as well as microfluidic based rapid antigen test. Their findings showed enhanced sensitivity for the rapid microfluidic immunofluorescence method compared to the lateral flow antigen tests.  This level of specificity empowers our ability to go back to “normal”.

The power of next generation point of care diagnostics was discussed at the recent American Association for Clinical Chemistry (AACC) Annual Conference in Chicago this summer. The discussion presented data-backed insights on the impact of LumiraDx advanced microfluidic technology over lateral flow point-of-care antigen tests, and the role of these rapid immunoassays in response to the COVID-19 pandemic.

LumiraDx, established in 2014, is transforming community-based healthcare by providing fast, accurate, and comprehensive diagnostic information to healthcare providers at the point of need, thereby enabling better medical decisions and improved patient outcomes at a much lower cost.

As the Scientific & Clinical Affairs Vice President at LumiraDx, I spoke alongside Dr. Paul Drain, Associate Professor at the University of Washington in the Departments of Global Health, Medicine (Infectious Diseases), and Epidemiology at the session. Dr. Drain presented his prospective validation study of the LumiraDx severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid antigen test, which uses a high-sensitivity, microfluidic immunoassay to detect the nucleocapsid protein of SARS-CoV-2 for diagnosing acute coronavirus disease 2019 (COVID-19) in adults and children across point of care settings.

The study showed that, among 512 participants, the LumiraDx SARS-CoV-2 Ag has a 97.6% positive agreement to RT PCR in patients up to 12 days following symptom onset, and 100% PPA up to Ct 33. These findings testify to the effectiveness of rapid, high-sensitivity assay using nasopharyngeal or anterior nasal sampling, offering significant improvements for diagnosing acute SARS-CoV-2 infection in clinic- and community-based settings. Dr. Drain also shared more recent data showing that differences between Delta and Omicron variants did not affect the performance of the LumiraDx SARS-CoV-2 Antigen Test

As we look ahead, immediacy is central to meeting patient care needs and optimizing provider decision making. Given the looming challenges of future pandemics, we should support policies that invest in integrated, scalable diagnostic solutions, which we can deploy rapidly at the point of care, especially in communities where little healthcare infrastructure is present. This will enable effective decision-making at the point of need, increase access to care, save health care costs, and improve patient outcomes.

Brian K. DuChateau, Ph.D., D(ABMLI) is a board certified clinical laboratory immunologist who received his Ph.D. in immunology and medical microbiology from the University of Wisconsin-Madison and completed a post-doctoral residency in clinical immunology at the Chicago Medical School.  Dr. DuChateau has over 20 years of experience as a clinical laboratory director and 12 years of in vitro diagnostics (IVD) experience and currently serves as the LumiraDx Vice President of US Scientific and Clinical Affairs.