APHL 2021 Poster Abstracts
Comparison of Multiple Nucleic Acid Extraction Platforms for the Detection of SARS-CoV-2 in Nasopharyngeal Specimens
A . Roden , P . Iwen and E . Mccutchen , Nebraska Public Health Laboratory , Omaha , NE
Background : Laboratory testing for SARS-CoV-2 ( SC2 ) has evolved during the COVID-19 pandemic to involve numerous changes with instrumentation and reagents . This study was done to evaluate multiple extraction platforms to define optimal testing platforms for detection .
Methods : RNA was isolated from nasopharyngeal swabs using several automated nucleic acid isolation platforms : the ThermoFisher KingFisher Flex with the MagMAX Viral / Pathogen II Nucleic Acid Isolation Kit ( KFF ), Qiagen EZ1 Advanced XL with the EZ1 DSP Virus Kit ( EZ1 ), the Roche MagNA Pure Compact with the MagNA Pure Compact Total Nucleic Acid Isolation Kit I ( MPC ), and the Roche MagNA Pure LC with the MagNA Pure LC Total Nucleic Acid Kit ( MLC ). RNA was subsequently analyzed via RT-PCR on the Applied Biosystems 7500 Fast Dx using either the CDC 2019-Novel Coronavirus RT-PCR Diagnostic Panel ( CDC-2019 ) or the CDC Influenza SARS-CoV-2 Multiplex Assay ( Flu-SC2 ). Cycle threshold ( Ct ) values for the SC2 positive samples were compared across the different isolation methods as well as the two RT-PCR assays to evaluate their combined performance .
Results : A total of 10,367 specimens yielded SC2 positive results following RT-PCR . Resultant Cts for the SC2 targets ( CDC2019 ) showed a significant increase in the percentage of positives detected at Ct levels between12-25 for those specimens with RNA isolated using the KFF ( 51.48 %) as compared to RNA isolated on the other , lower throughput , nucleic acid isolation instruments ( 45.13 %). Upon evaluation of the results of the SC2 positive specimens analyzed using the Flu-SC2 , the Cts from the Flu SC2 assay also showed higher percentages ( 55.93 %) ≤25 as compared those achieved from the CDC2019 assay ( 51.48 %).
Conclusion : The decrease in Cts observed with the KFF when used with the Flu-SC2 showed that these methods used together produced an overall higher sensitivity in the detection of SC2 when compared to the other methods . This combination may also be beneficial for testing of specimens with a decreased viral load such as nasal swabs and saliva , to increase the sensitivity of testing .
Presenter : Amy Roden , Nebraska Public Health Laboratory , amy . roden @ unmc . edu
SARS-CoV-2 Point of Care Testing in High-Risk Population to Improve Public Health Response
A . Bauer , K . Schieble , B . Pfotenauer , M . Khubbar and S . Bhattacharyya , City of Milwaukee Health Department
Introduction : Rapid molecular diagnostic testing landscape with regards to the current SARS-CoV-2 pandemic has emerged as integral part of public health response . To advance the health and equity of Milwaukeeans , Milwaukee Health Department Laboratory ( MHDL )’ s goal was to support and expand community testing capacity for quicker , more easily accessible COVID-19 testing for those most at-risk . With the ease of use , quick reliable results , and system to confirm the results obtained , this initiative presented a unique opportunity to help mitigate the spread of COVID-19 in non-traditional settings . MHDL led the deployment of 15 Abbott ID NOW analyzers to the most vulnerable and high-risk communities within our city .
Methods : In April 2020 , WI DHS reached out to MHDL regarding the availability of 15 Abbott ID instruments that HHS issued to Wisconsin . MHDL connected with various community partners that serve at-risk populations to gauge interest in receiving rapid ID NOW units for COVID-19 testing . As part of the analyzer deployment process , sites were provided corresponding training and assistance to ensure CLIA requirements were met with regards to testing and reporting to the local and state public health entities . Per FDA EUA recommendation , ID Now negative samples were confirmed at MHDL using SARS-CoV-2 PCR testing . This effort was in part to assess the frequency of false negative results and ensure that the ID NOW COVID-19 tests were not missing a significant number of truly positive patients .
Results : As the pandemic persisted and evolved , MHDL analyzed ID NOW confirmatory testing from select partner sites . For 11 weeks , two local universities , a homeless shelter and a free clinic were provided stickers to place on all requisitions accompanying COVID-19 swabs being sent for negative confirmatory testing . Of 1,401 confirmatory tests , 86 had discrepant results , indicating a 93.86 % agreement between ID NOW and confirmatory PCR testing . Also during that time those partner sites identified 519 positive patients at POC . By deploying ID NOW units , MHDL was able to reduce in-house testing volume by 4.55 %; this was critically important to laboratory operations as there was a surge in testing for all sampling sites , not just those with ID NOW units .
Conclusion : The use of the rapid molecular identification in high-risk and / or underserved populations had a positive impact in controlling the spread of COVID-19 in the community . MHDL ’ s partnering with community sites allowed for identifying COVID-19 positive patients using the ID NOW in real-time , aiding rapid isolation , and to begin contact tracing in order to reduce the spread in the community . Turn-around time of less than an hour , as compared to 24-48 hrs . with SARS-CoV-2 molecular reference testing , allows for quicker time to execute mitigation strategies .
Presenter : Amy Bauer , City of Milwaukee Health Department , abauer @ milwaukee . gov
Evaluation of an Automated Multiplex Assay for the Detection of SARS-CoV-2 IgG Antibodies to RBD , S1 , S2 , and N
H . Scholz , R . Walker , T . Williamson , J . Ford and C . Ferrero , Bio-Rad Laboratories , Hercules , CA
Objectives : SARS-CoV2 has caused a global pandemic since early 2020 . Bio-Rad Laboratories has designed the BioPlex 2200 SARS-CoV-2 IgG Panel , a highly specific , multiplex , IgG serology assay that provides a composite total result as well as individual antibody levels to four SARS-CoV-2 structural proteins . The BioPlex 2200 SARS-CoV-2 IgG Panel screens ( CoV-2 IgG ) and individually quantifies IgG antibodies to the receptor-binding domain ( RBD ), spike 1 ( S1 ), spike 2 ( S2 ), and nucleocapsid ( N ) proteins of SARS- CoV-2 . Here we evaluated the specificity and clinical sensitivity of the BioPlex 2200 SARS-CoV-2 IgG Panel .
Method : The BioPlex 2200 SARS-CoV-2 IgG panel employs fluoromagnetic dyed beads , each coated with RBD , S1 , S2 , or N protein . The RBD , S1 , S2 , and N protein-coated fluoromagnetic beads possess unique fluorescent signatures used to identify the presence of IgG antibodies to SARS-CoV-2 in a two-step assay kit .
COVID-19
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Summer 2021 LAB MATTERS 47 |