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Fagg J, Beale R, Futschik ME, Turek E, Chapman D, Halstead S, Jones M, Cole-Hamilton J, Gunson R, Sudhanva M, Klapper PE, Vansteenhouse H, Tunkel S, Dominiczak A, Peto TE, Fowler T. Swab pooling enables rapid expansion of high-throughput capacity for SARS-CoV-2 community testing. J Clin Virol 2023; 167:105574. [PMID: 37639778 DOI: 10.1016/j.jcv.2023.105574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023]
Abstract
BACKGROUND The challenges of rapid upscaling of testing capacity were a major lesson from the COVID-19 pandemic response. The need for process adjustments in high-throughput testing laboratories made sample pooling a challenging option to implement. OBJECTIVE This study aimed to evaluate whether pooling samples at source (swab pooling) was as effective as qRT-PCR testing of individuals in identifying cases of SARS-CoV-2 in real-world community testing conditions using the same high-throughput pipeline. METHODS Two cohorts of 10 (Pool10: 1,030 participants and 103 pools) and 6 (Pool6: 1,284 participants and 214 pools) samples per pool were tested for concordance, sensitivity, specificity, and Ct value differences with individual testing as reference. RESULTS Swab pooling allowed unmodified application of an existing high-throughput SARS-Cov-2 testing pipeline with only marginal loss of accuracy. For Pool10, concordance was 98.1% (95% Confidence interval: 93.3-99.8%), sensitivity was 95.7% (85.5-99.5%), and specificity was 100.0% (93.6-100.0%). For Pool6, concordance was 97.2% (94.0-99.0%), sensitivity was 97.5% (93.7-99.3%), and specificity was 96.4% (87.7-99.6%). Differences of outcomes measure between pool size were not significant. Most positive individual samples, which were not detected in pools, had very low viral concentration. If only individual samples with a viral concentration > 400 copies/ml (i.e. Ct value < 30) were considered positive, the overall sensitivity of pooling increased to 99.5%. CONCLUSION The study demonstrated high sensitivity and specificity by swab pooling and the immediate capability of high-throughput laboratories to implement this method making it an option in planning of rapid upscaling of laboratory capacity for future pandemics.
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Affiliation(s)
- Jamie Fagg
- Royal Free London NHS Foundation Trust, London, UK
| | - Rupert Beale
- Royal Free London NHS Foundation Trust, London, UK; University College London, Division of Medicine, Royal Free Hospital, London, UK
| | - Matthias E Futschik
- UK Health Security Agency, London, UK; Faculty of Health, School of Biomedical Sciences, University of Plymouth, Plymouth, UK
| | | | | | | | - Marc Jones
- Lighthouse Labs, University of Glasgow, UK
| | | | - Rory Gunson
- West of Scotland Specialist Virology Centre, Glasgow, UK
| | - Malur Sudhanva
- UK Health Security Agency, London, UK; King's College Hospital NHS Foundation Trust, London, UK
| | - Paul E Klapper
- UK Health Security Agency, London, UK; University of Manchester, Manchester, UK
| | | | | | | | | | - Tom Fowler
- UK Health Security Agency, London, UK; William Harvey Research Institute, Queen Mary University of London, London, UK.
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Erster O, Levy I, Kabat A, Mannasse B, Levy V, Assraf H, Azar R, Ben-Zvi H, Bradenstein R, Bunder O, Fadeela A, Keren-Naus A, Peretz A, Roif-Kaminsky D, Saleh L, Schreiber L, Schwartz O, Shaked-Mishan P, Sorek N, Strauss M, Steinberg R, Treygerman O, Zisman-Rozen S, Yishai R, Tejman-Yarden N, Mendelson E, Sofer D. A Multi-Laboratory Evaluation of Commercial Monkeypox Virus Molecular Tests. Microbiol Spectr 2023; 11:e0022523. [PMID: 37140382 PMCID: PMC10269769 DOI: 10.1128/spectrum.00225-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
In this report, we describe the first national scale multi-laboratory evaluation of monkeypox virus (MPXV) DNA commercial PCR kits. The objective of this study was to evaluate 2 kits by different diagnostic laboratories across Israel. Ten standardized samples were tested simultaneously using the Novaplex (15 laboratories) and Bio-Speedy (seven laboratories) kits. An in-house assay based on previously published reactions was used as reference. Comparison of the results showed high intra-assay agreement between laboratories, with small variations for most samples. The in-house assay had an analytical detection limit of less than 10 copies per reaction. While the 2 commercial kits were able to detect specimens with low viral loads similarly to the in-house assay, significant differences were observed, in the Cq values and relative fluorescence (RF), between the assays. The RF signal of the in-house and Bio-Speedy assays ranged between 5,000 and 10,000 RFU, while the signal in the Novaplex assay was less than 600 RFU. Due to the kit measurement protocol, the Cq values of the Bio-Speedy kit were 5 to 7.5 cycles lower than those of the in-house assay. On the contrary, the Cq values of the Novaplex kit were significantly higher than those of the in-house assay, with differences of 3 to 5 cycles per sample. Our results suggest that while all assays were similar in their overall sensitivity, direct comparison of Cq values between them may be misleading. To our knowledge, this is the first methodical evaluation of commercial MPX test kits. We therefore anticipate that this study would help diagnostic laboratories in choosing a specific MPX detection assay. IMPORTANCE To the best of our knowledge, this study is the first methodical evaluation of commercial kits designed for Monkeypox virus detection. This was done by performing the same tests using the same sample set in multiple laboratories, simultaneously, on a national scale. It therefore provides important and unique information on the performance of such kits and provides a guideline for choosing the assay of choice for monkeypox virus diagnosis in a standard diagnostic laboratory. It also demonstrates potential complications when trying to compare the results of different assays, even when testing exactly the same samples, under identical conditions.
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Affiliation(s)
- Oran Erster
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Itzchak Levy
- Infectious Diseases Unit, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Areej Kabat
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Batya Mannasse
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Virginia Levy
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Hadar Assraf
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Roberto Azar
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Haim Ben-Zvi
- Beilinson-Rabin Medical Center, Petach Tikva, Israel
| | | | - Olga Bunder
- Shamir Medical Center, Beer Yaacov Zerifin, Israel
| | | | | | - Avi Peretz
- The Baruch Padeh Medical Center, Poriya, Tiberias, Israel
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | | | - Lolu Saleh
- Beilinson-Rabin Medical Center, Petach Tikva, Israel
| | | | | | | | - Nadav Sorek
- Assuta Ashdod University Hospital, Ashdod, Israel
| | | | | | | | | | - Ruth Yishai
- Department of Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - Noa Tejman-Yarden
- Department of Laboratories, Public Health Services, Ministry of Health, Jerusalem, Israel
| | - Ella Mendelson
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
- School of Public Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Danit Sofer
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
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Uršič T, Kogoj R, Šikonja J, Roškarič D, Virant MJ, Bogovič P, Petrovec M. Performance of nasopharyngeal swab and saliva in detecting Delta and Omicron SARS-CoV-2 variants. J Med Virol 2022; 94:4704-4711. [PMID: 35642439 PMCID: PMC9348014 DOI: 10.1002/jmv.27898] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
A prospective cohort study was conducted during the Delta and Omicron severe acute respiratory syndrome coronavirus type 2 (SARS‐CoV‐2) epidemic waves from paired nasopharyngeal swab (NPS or NP swab) and saliva samples taken from 624 participants. The study aimed to assess if any differences among participants from both waves could be observed and if any difference in molecular diagnostic performance could be observed among the two sample types. Samples were transported immediately to the laboratory to ensure the highest possible sample quality without any freezing and thawing steps before processing. Nucleic acids from saliva and NPS were prospectively extracted and SARS‐CoV‐2 was detected using a real‐time reverse‐transcription polymerase chain reaction. All observed results were statistically analyzed. Although the results obtained with NP and saliva agreed overall, higher viral loads were observed in NP swabs regardless of the day of specimen collection in both SARS‐CoV‐2 epidemic waves. No significant difference could be observed between the two epidemic waves characterized by Delta or Omicron SARS‐CoV‐2. To note, Delta infection resulted in higher viral loads both in NP and saliva and more symptoms, including rhinorrhea, cough, and dyspnea, whereas Omicron wave patients more frequently reported sore throat. An increase in the mean log RNA of SARS‐CoV‐2 was observed with the number of expressed symptoms in both waves, however, the difference was not significant. Data confirmed that results from saliva were concordant with those from NP swabs, although saliva proved to be a challenging sample with frequent inhibitions that required substantial retesting.
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Affiliation(s)
- Tina Uršič
- University of Ljubljana, Faculty of Medicine University, Institute of Microbiology and Immunology, Ljubljana, Slovenia
| | - Rok Kogoj
- University of Ljubljana, Faculty of Medicine University, Institute of Microbiology and Immunology, Ljubljana, Slovenia
| | - Jaka Šikonja
- University of Ljubljana, Faculty of Medicine University, Institute of Microbiology and Immunology, Ljubljana, Slovenia
| | - Damijana Roškarič
- University of Ljubljana, Faculty of Medicine University, Institute of Microbiology and Immunology, Ljubljana, Slovenia
| | - Monika Jevšnik Virant
- University of Ljubljana, Faculty of Medicine University, Institute of Microbiology and Immunology, Ljubljana, Slovenia
| | - Petra Bogovič
- University Clinical Centre Ljubljana, Department of Infectious Diseases, Slovenia
| | - Miroslav Petrovec
- University of Ljubljana, Faculty of Medicine University, Institute of Microbiology and Immunology, Ljubljana, Slovenia
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