COVIDSeq as Laboratory Developed Test (LDT) for Diagnosis of SARSCoV- 2 Variants of Concern (VOC)
Author(s): Rob E Carpenter, Vaibhav K Tamrakar, Sadia Almas, Emily Brown, Rahul Sharma
Rapid classification and detection of SARS-CoV-2 variants have been critical in comprehending the virus's transmission dynamics. Clinical manifestation of the infection is influenced by comorbidities such as age, immune status, diabetes, and the infecting variant. Thus, clinical management may differ for new variants. For example, some monoclonal antibody treatments are variant-specific. Yet, a U.S. Food and Drug Administration (FDA)-approved test for detecting the SARS-CoV-2 variant is unavailable. A laboratory-developed test (LDT) remains a viable option for reporting the infecting variant for clinical intervention or epidemiological purposes. Accordingly, we have validated the Illumina COVIDSeq assay as an LDT according to the guidelines prescribed by the College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). The limit of detection (LOD) of this test is Ct<30 (~15 viral copies) and >200X genomic coverage, and the test is 100% specific in the detection of existing variants. The test demonstrated 100% precision in inter-day, intra-day, and intra-laboratory reproducibility studies. It is also 100% accurate, defined by reference strain testing and split sample testing with other CLIA laboratories. Advanta Genetics LDT COVIDSeq has been reviewed by CAP inspectors and is under review by FDA for Emergency Use Authorization.