Abstract Unmet Need: q-rtPCR technology has dominated COVID-19 diagnostics and public health screening. Independent of the test developer, q-rtPCR has been shown to have an unusually high false negative rate: 15% up to 48% (1). According to the Covid Tracking Project. as of May 16th, 2020, 11 Million COVID-19 tests had been administered in the US (2). With 15% false negative rate, approximately 1.65M people would be falsely classified as free of infection. As might be expected, meta-analysis has shown that the false negative rate for q-rtPCR “explodes” before day 7 of infection (3) when viral load is still low, to render q-rtPCR ineffective as a tool for detecting weakly symptomatic carriers early, while also lessening its value in epidemiology (4). The Solution: PathogenDx has invented, patented and developed a microarray-based test, DetectX-Rv, and has submitted it for FDA-EUA review to screen for COVID-19 in NP swabs. The microarray has the capacity to test for multiple viral analytes in parallel with [SARS-CoV-2] as the primary analyte under FDA submission. Content Enhancement. We propose here the addition of a newly identified COVID-19 clade variant, which has been hypothesized by others to be more infective (5). DetectX-Rv already contains content needed to test SARS-CoV-2 plus multiple other coronavirus [SARS-CoV, MERS-CoV, CoV 229E,CoV OC43, CoV NL63, CoV HKU1] plus influenza + [PanA & Pan B] which are defined as a set as a “Pan-Respiratory” Virus Test. However for the development proposed in this RO1, this “extra” coronavirus content will be rationally modified and used instead as a large set of specificity controls. Other sources of funding outside this RO1 will be used to develop the full Pan-Respiratory virus content, as a separate product. Based on the work completed thus far, including April 15, 2020 filing to the FDA, we propose that with RO1 funding, the new test variant (DetectX-Rv-v2) can be made ready (by Q2) for deployment with NP swab collection as an automated 96 array/SBS plate COVID-19 test (@576 tests/shift). Sensitivity Improvement. The DetectX-Rv test is based on two Tandem Endpoint PCR reactions in series [Enrichment + Labeling] coupled to microarray hybridization. This technical approach gives rise to detection at single nucleotide resolution over a 6-log sample input dynamic range. Most importantly, the [Tandem PCR + Hybridization] assay routinely generates a Lowest Limit of Detection (LLOD) <1 genome per reaction. We anticipate that with this approach, we will routinely detect COVID-19 (signal/noise >20x background) at only 1 viral genome per reaction. Preliminary data, including that submitted to the FDA EUA program, suggests that the LLOD for DetectX-Rv will be roughly 10x lower than for an optimized q-RT-PCR reaction. Thus, with the DetectX-Rv test, COVID-19 should be routinely detected at 100 virus particles/swab. Specificity Enhancement. DetectX-Rv (144 tests) has enormous test capacity relative to q-rtPCR, whi...