The Time for Widespread Adoption of MDx Testing for GAS Pharyngitis has Arrived: an Interview with Scott Sugden, PhD

Introduction

Rapid and accurate detection of group A streptococcus (GAS) pharyngitis is increasingly important given the resurgence of GAS infections, including invasive disease, following the COVID-19 pandemic. In a comprehensive review article published in Expert Review of Molecular Diagnostics,¹ Scott M. Sugden, Ph.D., Sr. Director of Medical Affairs at Cepheid Canada, discusses how molecular diagnostic testing represents a significant advancement in GAS detection and why now is the ideal time for healthcare providers to embrace molecular testing for GAS pharyngitis, particularly in point-of-care settings.

The Cepheid Editorial Team had the opportunity to speak with Dr. Sugden about his article to learn more about this important topic. Read on to learn more about key considerations in the adoption of molecular testing, including practical solutions to common implementation concerns such as budget, training, infrastructure, and clinical validity. 

Q: Dr. Sugden, why is rapid and accurate diagnosis of GAS pharyngitis particularly critical for healthcare professionals today? 
A: Fast diagnosis of GAS pharyngitis has several important outcomes. It allows doctors to initiate appropriate antibiotic treatment in a timely fashion. This lowers the risk of serious complications of infection such as Acute Rheumatic Fever and Rheumatic Heart Disease, and may help prevent further GAS transmission. Reducing transmission could lower the total GAS burden in the community, which may help reduce cases of severe invasive GAS as well. Accurate diagnosis also reduces unnecessary antibiotic use, thus reducing antimicrobial resistance.

Q: What are the limitations of traditional GAS testing methods? 
A: Traditional culture, while highly accurate, requires up to 48 hours for results, potentially delaying necessary treatment. Rapid antigen diagnostic tests, which detect GAS proteins, offer quicker results but can miss positive cases due to lower sensitivity. 

Q: How does molecular GAS testing compare to traditional diagnostic methods? 
A: Molecular GAS testing allows healthcare professionals to “have their cake and eat it too.” By combining the high sensitivity of culture-based techniques with the fast turnaround and simplicity of rapid antigen diagnostic tests, molecular testing for GAS pharyngitis can lead to more effective and timely treatment. This can lower the total GAS burden and reduce GAS-related morbidities while simultaneously helping to combat antimicrobial resistance by lowering the total amount of unnecessary antibiotics prescribed.

Q: How suitable is molecular diagnostic testing for point-of-care environments? 
A: Molecular diagnostic testing is great for point-of-care settings. Several molecular tests are specifically approved for point-of-care use without a recommendation for culture confirmation of negative results. This means you can have a rapid and responsible “test and treat” model, where patients get their results and leave with a prescription, if needed, all in one visit. This is especially crucial in reducing barriers to healthcare in remote areas. 

Q: Why is decentralization of GAS testing particularly important in remote geographic areas? 
A: It’s a question of health equity. Some of the highest burdens of GAS and its complications are found in remote geographic areas. And many high-burden remote regions have significant Indigenous populations. We need to make sure everyone has access to the best possible care. Implementation of GAS testing must integrate cultural considerations into planning. Establishing culturally responsive partnerships with local Indigenous leadership will be crucial.

Q: What are the main barriers to responsible and widespread implementation of molecular testing for GAS? 
A: The technologies for molecular testing for GAS pharyngitis are ready and available, but many of the supporting factors required to implement these technologies responsibly are lagging, particularly in point-of-care environments. We need governments and healthcare organizations to provide funding and incentives to facilitate adoption. We also need them to develop the required transportation and electrical infrastructures for testing to become widespread, especially in remote regions. Medical society guidelines need to be updated to inform molecular test users of best practices.

Q: How should healthcare providers think about budgetary concerns surrounding the implementation of molecular testing for GAS? 
A: There can be initial molecular testing equipment investments. But at many sites, equipment used during the SARS-CoV-2 pandemic are already available, significantly reducing the need for new capital expenditure. And although per-test costs are typically higher for molecular tests compared to rapid antigen tests, the overall economic benefits of avoiding complications and unnecessary antibiotic use may result in net savings for healthcare systems.

Q: Regarding technical training, how can healthcare settings smoothly transition to molecular testing? 
A: Many molecular tests are classified as low complexity CLIA-waived or near-patient tests, which require minimal training. And skills from rapid antigen and culture testing, such as swab collection, can easily transition to molecular testing, simplifying implementation even in non-traditional lab settings like pharmacies.

Q: How can quality management challenges in point-of-care environments be effectively addressed? 
A: I think solutions developed for SARS-CoV-2 testing during the COVID-19 pandemic provide valuable precedents. Many existing molecular testing networks established for SARS-CoV-2 testing can be updated to incorporate GAS testing with minimal adjustments to procedures and quality programs. Guidelines from governments and other authorities should be updated to include molecular testing and should offer clear recommendations on quality and data management practices for point-of-care settings. Again, this is especially important in remote locations.

Q: Final thoughts on the future implementation of molecular testing for GAS? 
A: Molecular testing represents state-of-the-art technology for GAS pharyngitis detection, combining accuracy, speed, and ease of use. With continued advancements in testing technology and supporting infrastructure, alongside necessary guideline updates, healthcare providers should proactively plan for widespread molecular testing implementation. The molecular age for GAS testing has undoubtedly arrived, and with it comes the promise of significant clinical and societal benefits.