VALCOR: a protocol for the validation of SARS-corona virus-2 assays

Abstract

Background Testing for SARS-CoV-2, together with vaccination, is one of the most vital strategies in curbing the current COVID-19 pandemic. The pandemic has led to an unprecedented need for diagnostic testing and the rapid emergence of an abundance of commercial assays on the market. Due to the nature of the pandemic and in the interest of health protection, many of these assays received provisional authorisation for emergency use without thorough validation. To limit false negative and false positive results, it is key to define common criteria that SARS-CoV-2 assays need to fulfil. VALCOR or “VALidation of SARS-CORona Virus-2 assays” is a protocol designed to set up a framework for test validation of SARS-CoV-2 virus assays. Objectives VALCOR is a study protocol for the validation of assays used for confirmation of the presence of SARS-CoV-2 in patients with COVID-19 disease or the screening of carriers of SARS-CoV-2 virus by the identification of viral RNA in oropharyngeal and/or nasopharyngeal specimens or other specimens from the human respiratory tract. Methods The VALCOR panel of samples will contain clinical human specimens and standardised artificial specimens. The collection of clinical specimens will include nasopharyngeal or oropharyngeal specimens or other specimens from the respiratory tract obtained from COVID-19 patients and healthy carriers of SARS-CoV-2 as well as specimens from subjects not carrying SARS-CoV-2. Artificial specimens include calibrated amounts of viral RNA of SARS-CoV-2 sequences provided by established competent agencies that produce reference materials for the assessment of the limit of detection of each assay. The panel of samples are sent from a central reference laboratory (having access to biobanks of clinical specimens tested already for SARS-CoV-2 with a reference comparator assay) to participating laboratories for testing with a SARS-CoV-2 index assay that requires evaluation. Discussion VALCOR provides a harmonised and standard framework to benchmark the testing performance of SARS-CoV-2 assays that are rapidly evolving. As the pandemic incited an urgent need for testing capacity, there is a gap in the comprehensive validation of SARS-CoV-2 assays. This study will generate comprehensive validation data for assays used for the diagnosis of SARS-CoV-2 and may serve as a basis for other validation protocols.

Assessment of the clinical and analytical performance of three Seegene Allplex SARS-CoV-2 assays within the VALCOR framework

“…The full protocol of VALCOR and the composition of the VALCOR samples’ panel were described previously ( 11 ). In brief, three types of samples were investigated.…”

“…Here, assay validation with clinical samples is recommended to evaluate clinical accuracy. With this objective, the VALCOR (VALidation of SARS-CORona Virus-2 assays) protocol was developed to validate SARS-CoV-2 assays in a clinical framework ( 11 ), as previously demonstrated with the validation of the Aptima SARS-CoV-2 assay (Hologic, MA, USA) ( 12 ).…”

“…In this study, we validate the clinical accuracy of three Seegene Allplex SARS-CoV-2 assays (index assays) using clinical samples collected according to the VALCOR protocol ( 11 ). The three Seegene Allplex SARS-CoV-2 assays are Allplex SARS-CoV-2 (abbreviated as Allplex-SC2), Allplex SARS-CoV-2 Fast PCR (abbreviated as Allplex-SC2Fast) and the combi assay co-detection Influenza A and B along with respiratory syncytial virus, and the Allplex SARS-CoV-2/FluA/FluB/respiratory syncytial virus (RSV) (abbreviated as Allplex-SC2FabR).…”

Assessment of the clinical and analytical performance of the Aptima SARS-CoV-2 assay using the VALCOR protocol

“…VALCOR is a protocol designed to set up a framework for test validation of SARS-CoV-2 virus assays and is inspired by the principles of VALGENT (VALidation of HPV GENotyping Test), which is a world-widely recognized forum for HPV test comparison and validation [12]. The full protocol of VALCOR is described elsewhere [11].…”

“…EUA was essential to address the need to make diagnostic assays available quickly however it is still vital that such commercial assays become FDA cleared or approved according to a systematic standardized validation framework. In this present study, we aim to evaluate the test performance of the automated Aptima SARS-CoV-2 assay (Hologic ® Panther System) using clinical samples collated according to the VALCOR protocol [11] (acronym for "VALidation of SARS-CORona Virus-2 assays").…”