Introduction: Testing for active SARS-CoV-2 infection is a fundamental tool in the public health measures taken to control the COVID-19 pandemic. Because of the overwhelming use of SARS-CoV-2 reverse transcription (RT)-PCR tests worldwide, the availability of test kits has become a major bottleneck and the need to increase testing throughput is rising. We aim to overcome these challenges by pooling samples together, and performing RNA extraction and RT-PCR in pools. Methods: We tested the efficiency and sensitivity of pooling strategies for RNA extraction and RT-PCR detection of SARS-CoV-2. We tested 184 samples both individually and in pools to estimate the effects of pooling. We further implemented Dorfman pooling with a pool size of eight samples in large-scale clinical tests. Results: We demonstrated pooling strategies that increase testing throughput while maintaining high sensitivity. A comparison of 184 samples tested individually and in pools of eight samples showed that test results were not significantly affected. Implementing the eight-sample Dorfman pooling to test 26 576 samples from asymptomatic individuals, we identified 31 (0.12%) SARS-CoV-2 positive samples, achieving a 7.3-fold increase in throughput. Discussion: Pooling approaches for SARS-CoV-2 testing allow a drastic increase in throughput while maintaining clinical sensitivity. We report the successful large-scale pooled screening of asymptomatic

Pooling multiple swab samples prior to RNA extraction and real-time reverse-transcription (RT-PCR) analysis has been proposed as a strategy to reduce costs and increase throughput of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tests. However, reports on practical large-scale group testing for SARS-CoV-2 have been scant. Key open questions concern reduced sensitivity due to sample dilution, the rate of false positives, the actual efficiency (number of tests saved by pooling), and the impact of infection rate in the population on assay performance. Here we report an analysis of 133,816 samples collected between April-September 2020 and tested by Dorfman pooling for the presence of SARS-CoV-2. We spared 76% of RNA extraction and RT-PCR tests, despite the frequently changing prevalence (0.5%-6%). We observed pooling efficiency and sensitivity that exceeded theoretical predictions, which resulted from the non-random distribution of positive samples in pools. Overall, our findings support the use of pooling for efficient large-scale SARS-CoV-2 testing.

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BACKGROUND AIM Anemia is commonly associated with acute and chronic inflammation, but the mechanisms of their interaction are not clear. We investigated whether microRNA 122 (MIR122), which is generated in the liver and is secreted into the blood, is involved in the development of anemia associated with inflammation. METHODS We characterized the primary transcript of the human liverspecific MIR122 using northern blot, quantitative real-time PCR, and 3' and 5' RACE analyses. We studied regulation of MIR122 in human hepatocellular carcinoma (HCC) cell lines (Huh7 and HepG2) as well as in C57BL/6 and mice with disruption of the tumor necrosis factor gene (Tnf). Liver tissues were collected and analyzed by bioluminescence imaging or immunofluorescence. Inflammation in mice was induced by lipopolysaccharide (LPS) or by cerulein injections. Mice were given 4 successive injections of LPS, leading to inflammation-induced anemia. Steatohepatitis was induced with a choline-deficient high-fat diet. Hemolytic anemia was stimulated by phenylhydrazine injection. MIR122 was inhibited in mice by tail-vein injection of antogomiR-122 (an oligonucleotide antagonist of MIR122). MicroRNA and mRNA levels were determined by quantitative real time PCR. RESULTS The primary transcript of MIR122 spanned 5 kb, comprising 3 exons; the third encodes MIR122. Within the MIR122 promoter region we identified a nuclear factor-B (NF-B) binding site and demonstrated that RELA, as well as activators of NF-B (TNF and LPS), increased promoter activity of MIR122. Administration of LPS to mice induced secretion of MIR122 into blood, which required TNF. Secreted MIR122 reached the kidney and reduced expression of erythropoietin (Epo), which we identified as a MIR122 target gene. Injection of mice with antagomiR-122 increased blood levels of EPO, reticulocytes, and hemoglobin. We found an inverse relationship between blood levels of MIR122 and EPO in mice with acute pancreatitis or steatohepatitis, and also in patients with acute inflammation. CONCLUSION In mice, we found that LPS-induced inflammation increases blood levels of MIR122, which reduces expression of Epo in the kidney; this is a mechanism of inflammation-induced anemia. Strategies to block MIR122 in patients with inflammation could reduce the development or progression of anemia. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT AbstractBackground & Aim: Anemia is commonly associated with acute and chronic inflammation, but the mechanisms of their interaction are not clear. We investigated whether microRNA 122 (MIR122),...

Pooling multiple swab samples prior to RNA extraction and RT-PCR analysis was proposed as a strategy to reduce costs and increase throughput of SARS-CoV-2 tests. However, reports on practical large-scale group testing for SARS-CoV-2 have been scant. Key open questions concern reduced sensitivity due to sample dilution; the rate of false positives; the actual efficiency (number of tests saved by pooling) and the impact of infection rate in the population on assay performance. Here we report analysis of 133,816 samples collected at April-September 2020, tested by pooling for the presence of SARS-CoV-2. We spared 76% of RNA extraction and RT-PCR tests, despite the reality of frequently changing prevalence rate (0.5%-6%). Surprisingly, we observed pooling efficiency and sensitivity that exceed theoretical predictions, which resulted from non-random distribution of positive samples in pools. Overall, the findings strongly support the use of pooling for efficient large high throughput SARS-CoV-2 testing.