The worldwide spread of the COVID-19 pandemic has stressed clinical laboratories in numerous dimensions. Supply chain management, preanalytical throughput, analytical throughput, and extreme variances in testing demand have all pushed testing facilities to their limits and forced them to take on new assays, develop new protocols, and otherwise adapt to a much higher and more urgent throughput. Clinical Pathology Laboratories is one such testing firm, and their scientific director, Dr. Scott Hunicke-Smith, recently gave a presentation about Clinical Pathology Laboratories’ SARS-CoV-2 testing journey.
Webinar: Clinical Laboratory Experience with TaqPath COVID-19 Testing
Scott Hunicke-Smith, PhD
Clinical Pathology Laboratories
Watch the full presentation
Clinical Pathology Laboratories is part of Sonic Healthcare Worldwide, based in Australia and present in Australia, New Zealand, many countries in western Europe, and the United States. Clinical Pathology Laboratories provides testing services for SARS-CoV-2 as an extension of its testing services for numerous other conditions. They were among the first labs to bring pap testing services to central Texas in the 1940s and 1950s, among other claims to fame, so adding SARS-CoV-2 testing to their repertoire was an obvious choice. They implemented several different testing protocols, including immunogloblulin G (IgG) assays for serology testing, and among the options they explored and ultimately included in their portfolio was the Applied Biosystems® TaqPath COVID-19 Combo Kit.
The TaqPath COVID-19 Combo Kit, built on the strong technical foundation and substantial manufacturing capacity of Thermo Fisher Scientific while also leveraging the workforce of molecular biologists trained and experienced in real-time PCR techniques, enabled Clinical Pathology Laboratories to be part of the unprecedented scale-up in test capacity that the emergence of COVID-19 required around the world. The TaqPath assay is notably different from what high-volume reference and testing labs would ordinarily use, amenable to automation but also highly customizable and scalable for different workflows and levels of analysis.
This makes it different from other high-throughput assays, which offer fewer options for end-user customization. Once TaqPath gained the necessary FDA Emergency Use Authorization of its 384-well format, Clinical Pathology Laboratories discarded an in-house 384-well assay in favor of TaqPath’s customizability. While it has not replaced all of Clinical Pathology Laboratories’s SARS-CoV-2 testing, the advantages of TaqPath have earned it prominence among their options.
TaqPath technology makes it easy to add additional controls and to track individual specimens throughout the measurement process, including across multiple platforms, making it unusually well-suited to a clinical testing environment. It has much higher throughput than the other qPCR systems that Dr. Hunicke-Smith’s team uses, which is critical to the current moment of high-volume testing for a dangerous, contagious pathogen. In order to get the most out of TaqPath products in their use case, Dr. Hunicke-Smith and his team added control steps, including a no-template control and an additional 1:4 positive control, which were much easier to add here than in other qPCR-based assays. These controls enabled them to add tools for tracking long-term stability of the assay, making it easier to confirm batch integrity and keep an eye on wear-and-tear on their equipment as it performs thousands of measurements.
Their additions also enable them to rapidly identify errors associated with individual plates, which is especially important for an assay like TaqPath, in which part of the preparation takes place on 96-well plates before transfer to the final 384-well plate. The 1:4 control in particular also enabled them to confirm the integrity of other readings, since its relationship to the standard control wells was predetermined and could serve as a standard against which to judge the effectiveness of the rest of the assay. The less customizable assays that Dr. Hunicke-Smith’s team also use may be simpler, but they do not provide this high-level information.
Dr. Hunicke-Smith’s detailed and multifaceted quality-control regimen, through these additional control steps, has enabled them to create advanced data analytics that will prove valuable as studies on SARSCoV-2 and the pandemic more broadly begin to unfold. Their data is refined enough to provide insight into the relationship between positive results on qPCR and antibody-serology assays performed on the same patients and to judge viral loads based on Ct values, helping to not only distinguish infected from uninfected test recipients but to understand how the infection proceeds over time and how immune systems react to it.
Whether in a start-up or a well-established laboratory, successful ongoing testing with the TaqPath COVID-19 Combo Kit that is responsive to the needs of patients and physicians requires acute attention to detail in traditional areas of laboratory operations including quality control, workflow, labor allocation, standardized processes, and technician training. As Dr. Hunicke-Smith found, the flexibility of the assay and associated analyses add additional challenges, but also comes with additional possibilities and additional potential.
TaqPath COVID-19 Combo Kit: For Emergency Use Authorization (EUA) only. For prescription use only. For in vitro diagnostic use.