RESUMO
BackgroundSince the beginning of the COVID-19 pandemic veterinary diagnostic laboratories have tested diagnostic samples for SARS-CoV-2 not only in animals, but in over five million human samples. An evaluation of the performance of those laboratories is needed using blinded test samples to ensure that laboratories report reliable data to the public. This interlaboratory comparison exercise (ILC3) builds on two prior exercises to assess whether veterinary diagnostic laboratories can detect Delta and Omicron variants spiked in canine nasal matrix or viral transport medium. MethodsInactivated Delta variant at levels of 25 to 1,000 copies per 50 L of nasal matrix were prepared for participants by the ILC organizer, an independent laboratory, for blinded analysis. Omicron variant at 1,000 copies per 50 L of transport medium was also included. Feline infectious peritonitis virus (FIPV) RNA was used as a confounder for specificity assessment. A total of 14 test samples were prepared for each participant. Participants used their routine diagnostic procedures for RNA extraction and real-time RT-PCR. Results were analyzed according to International Organization for Standardization (ISO) 16140 - 2:2016. ResultsThe overall results showed 93% detection for Delta and 97% for Omicron at 1,000 copies per 50 L (22-200 copies per reaction). The overall specificity was 97% for blank samples and 100% for blank samples with FIPV. No differences in Ct values were significant for samples with the same virus levels between N1 and N2 markers, nor between the two variants. ConclusionsThe results indicated that all ILC3 participants were able to detect both Delta and Omicron variants. The canine nasal matrix did not significantly affect SARS-CoV-2 detection. Impact StatementEnsuring accurate detection methods for SARS-CoV-2 is critical as veterinary diagnostic labs are testing both human and animal samples. This exercise used blinded test samples and provided high confidence in the sensitivity of methods in twenty-nine laboratories for detection of SARS-CoV-2 variants while addressing the impact of sample matrix. Importantly, the results indicated that variants and matrix do not impact detection results. Additionally, this article examined decision-making criteria for Ct cut-off values from different laboratories and encouraged them to review and potentially reassess their criteria to improve future performance. This knowledge will lead to higher confidence in laboratory detection of current and new SARS-CoV-2 variants and aid in establishing reasonable cut-off parameters for these diagnostics tests.
RESUMO
The coronavirus disease 2019 (COVID-19) pandemic presents a continued public health challenge across the world. Veterinary diagnostic laboratories in the U.S. use real-time reverse transcriptase PCR (RT-PCR) for animal testing, and many are certified for testing human samples, so ensuring laboratories have sensitive and specific SARS-CoV-2 testing methods is a critical component of the pandemic response. In 2020, the FDA Veterinary Laboratory Investigation and Response Network (Vet-LIRN) led the first round of an Inter-Laboratory Comparison (ILC) Exercise to help laboratories evaluate their existing real-time RT-PCR methods for detecting SARS-CoV-2. The ILC1 results indicated that all participating laboratories were able to detect the viral RNA spiked in buffer and PrimeStore molecular transport medium (MTM). The current ILC (ILC2) aimed to extend ILC1 by evaluating analytical sensitivity and specificity of the methods used by participating laboratories to detect three SARS-CoV-2 variants (B.1, B.1.1.7 (Alpha) and B.1.351 (Beta)). ILC2 samples were prepared with RNA at levels between 10 to 10,000 copies per 50 L MTM. Fifty-seven sets of results from 45 laboratories were qualitatively and quantitatively analyzed according to the principles of ISO 16140-2:2016. The results showed that over 95% of analysts detected the SARS-CoV-2 RNA in MTM at 500 copies or higher for all three variants. In addition, 81% and 92% of the analysts achieved a Level of Detection (LOD95eff. vol.) below 20 copies in the assays with nucleocapsid markers N1 and N2, respectively. The analytical specificity of the evaluated methods was over 99%. The study allowed participating laboratories to assess their current method performance, identify possible limitations, and recognize method strengths as part of a continuous learning environment to support the critical need for reliable diagnosis of COVID-19 in potentially infected animals and humans.
RESUMO
Since the beginning of the development of sunscreen products, efforts have been made to measure and quantify the protection performance of such products. Early on an in vivo method was established that allowed statements on the sun protection performance in humans. Later, by establishing defined basic and experimental conditions, the method became internationally standardized delivering the well-known sun protection factor (SPF). The method was widely used and is nowadays regarded as a gold-standard method. Further standardized methods were added shortly thereafter. However, shortcomings such as the confined radiation spectra used by the methods, the invasiveness, the complexity in their application, as well as their time- and cost-intensity promoted the development of alternative methods. The shortcomings were recently followed by another, namely, the large interlaboratory variances of the sun protection metrics SPFISO 24444. This all together shows that there is a justifiable need to explore the potential of alternative methods, to complement the existing methods, to serve as equivalents, or even to replace it in the future. Based on the work of Uhlig and coworkers, the authors propose to test the suitability of the alternative methods and their possible equivalency to the reference methods in a broad-based investigation, taking into account possible interlaboratory variances. A research program - developed by a consortium - is in public planning where stakeholders from research, industry, authorities, and the public can come together to facilitate and further advance standardization of the measurement of the sun protection performance. The authors give an insight into historical, technical--conceptual, and future developments of methods for -determining the protective performance of sun protection products.
