Results of a European-Wide External Quality Assessment (EQA) Scheme for Serological Detection of Anti-SARS-CoV-2 (CoVimm)-Pitfalls of Routine Application.

BACKGROUND: During the last two years, a variety of assays for the serological detection of antibodies to the new SARS-CoV-2 virus have been launched and used as part of standard care in many laboratories. The pace with which these tests have been introduced into routine care emphasizes the importance of quality measures for analytical methods, particularly with regard to the implications of results for clinical and epidemiologic decisions. Accuracy, reliability and comparability of analytical test results are thus essential, and here external quality assessment (EQA) is the most important quality assurance tool. It allows us to achieve harmonization of test methods as a prerequisite for a high standard of performance for laboratory and analytical techniques and their interpretation. METHODS: This EQA scheme consisted of pre-characterized clinical biospecimens dedicated to the analysis of anti-SARS-CoV-2 IgG total antibodies and differentiation into spike protein-specific IgG antibodies against SARS-CoV-2 (anti-S-SARS-CoV-2) and nucleocapsid-specific IgG antibodies against SARS-CoV-2 (anti-N-SARS-CoV-2). RESULTS: A total of 239 laboratories across Europe participated in this scheme, called CoVimm. In detail, 536 results for anti-SARS-CoV-2 IgG, 431 results for anti-S-SARS-CoV-2 IgG, and 200 results for anti-N-SARS-CoV-2 IgG were reported. Based on the pre-defined thresholds, the success rates for the determination of anti-S-SARS-CoV-2 IgG and anti-N-SARS-CoV-2 IgG were 96% and 90%, respectively. Interestingly, only 64% of the participating laboratories successfully passed the EQA scheme for the determination of total anti-SARS-CoV-2 IgG. CONCLUSIONS: This EQA revealed serious concerns regarding the reliability and appropriate use of anti-SARS-CoV-2 antibody assays in routine care. In addition to the wide heterogeneity of different assays used by participating laboratories, a lack of standardization and harmonization is also evident. This is of particular importance for reliable and clinically meaningful interpretation of test results.

Integrated diagnostics.

BACKGROUND: Integrated diagnostics is increasingly gaining scientific traction as it promises to address several challenges currently facing diagnostic medicine. These challenges range from the need for improved diagnostic accuracy to optimized timing of diagnostic procedures, to the variety of diagnostic markers and thus the complexity of their interpretation, and finally to economic pressure. METHODICAL INNOVATIONS: While many of these challenges may be difficult to solve with a monomodal approach, the integration of laboratory markers and imaging procedures promises to allow both disciplines to achieve their actual clinical potential. Combining complementary diagnostic approaches can help to improve the interpretation of measurements, provide a better cost-effectiveness particularly when cutting-edge techniques are used for specific indications, and facilitate optimized timing and rational choice of appropriate diagnostic approaches for disease surveillance. Furthermore, close interdisciplinary assessment of diagnostic results will increase diagnostic accuracy and will enable selection of specific patient cohorts at increased risk for certain diseases who are suitable for further testing. CONCLUSION: The potential of an integrated diagnostic approach represents a strategic goal for diagnostic disciplines as it achieves better visibility and greater clinical impact. In addition to close collaboration among relevant diagnostic experts, an appropriate structure for integrated data evaluation needs to be established to provide actionable health guidance so that integrated diagnostics can be implemented in standard care.

Identification of CT Imaging Phenotypes of Colorectal Liver Metastases from Radiomics Signatures-Towards Assessment of Interlesional Tumor Heterogeneity.

(1) Background: Tumoral heterogeneity (TH) is a major challenge in the treatment of metastatic colorectal cancer (mCRC) and is associated with inferior response. Therefore, the identification of TH would be beneficial for treatment planning. TH can be assessed by identifying genetic alterations. In this work, a radiomics-based approach for assessment of TH in colorectal liver metastases (CRLM) in CT scans is demonstrated. (2) Methods: In this retrospective study, CRLM of mCRC were segmented and radiomics features extracted using pyradiomics. Unsupervised k-means clustering was applied to features and lesions. Feature redundancy was evaluated by principal component analysis and reduced by Pearson correlation coefficient cutoff. Feature selection was conducted by LASSO regression and visual analysis of the clusters by radiologists. (3) Results: A total of 47 patients' (36% female, median age 64) CTs with 261 lesions were included. Five clusters were identified, and the categories small disseminated (n = 31), heterogeneous (n = 105), homogeneous (n = 64), mixed (n = 59), and very large type (n = 2) were assigned based on visual characteristics. Further statistical analysis showed correlation (p < 0.01) of clusters with sex, primary location, T- and N-status, and mutational status. Feature reduction and selection resulted in the identification of four features as a final set for cluster definition. (4) Conclusions: Radiomics features can characterize TH in liver metastases of mCRC in CT scans, and may be suitable for a better pretherapeutic classification of liver lesion phenotypes.

Economic assessment of molecular imaging in the oncology treatment process.

The development towards targeted treatments in oncology has been accompanied by significant improvements in molecular imaging. Yet, broad application of novel imaging techniques has partly been slowed down due to economical considerations. Building on the broad positive evidence of its diagnostic accuracy, modelling of effects on long-term costs and effectiveness may help to foster a broader application and acceptance of comprehensive molecular imaging techniques, such as PET/MRI. In this article, common economic evaluation techniques and cost-effectiveness analysis (CEA) evaluation methods will be introduced including Markov models and incremental cost-effectiveness ratios (ICER). This is complemented with a review of literature on recently published cost-effectiveness of molecular imaging. Additionally, the strategic relevance of CEAs for the molecular imaging community is discussed and combined with a global outlook.

Assessing the Quality of Serological Testing in the COVID-19 Pandemic: Results of a European External Quality Assessment (EQA) Scheme for Anti-SARS-CoV-2 Antibody Detection.

External quality assessment (EQA) is a key instrument for achieving harmonization, and thus a high quality, of diagnostic procedures. As reliable test results are crucial for accurate assessment of SARS-CoV-2 infection prevalence, vaccine response, and immunity, and thus for successful management of the ongoing COVID-19 pandemic, the Reference Institute for Bioanalytics (RfB) was the first EQA provider to offer an open scheme for anti-SARS-CoV-2 antibody detection. The main objectives of this EQA were (i) to gain insights into the current diagnostic landscape and the performance of serological tests in Europe and (ii) to provide recommendations for diagnostic improvements. Within the EQA, a blinded panel of precharacterized human serum samples with variable anti-SARS-CoV-2 antibody titers was provided for detection of anti-SARS-CoV-2 IgG, IgA, and IgM antibodies. Across the three distribution rounds in 2020, 284 laboratories from 22 countries reported a total of 3,744 results for anti-SARS-CoV-2 antibody detection using more than 24 different assays for IgG. Overall, 97/3,004 results were false for anti-SARS-CoV-2 IgG, 88/248 for IgA, and 34/124 for IgM. Regarding diagnostic sensitivity and specificity, substantial differences were found between the different assays used, as well as between certified and noncertified tests. For cutoff samples, a drop in the diagnostic sensitivity to 46.3% and high interlaboratory variability were observed. In general, this EQA highlights the current variability of anti-SARS-CoV-2 antibody detection, technical limitations with respect to cutoff samples, and the lack of harmonization of testing procedures. Recommendations are provided to help laboratories and manufacturers further improve the quality of anti-SARS-CoV-2 serological diagnostics.

Longitudinal assessment of anti-SARS-CoV-2 antibody dynamics and clinical features following convalescence from a COVID-19 infection.

INTRODUCTION: The longevity of antibody levels against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the duration of immunity are current topics of major scientific interest. Antibody kinetics during the acute phase are well studied, whereas the long-term kinetics are yet to be determined, with contradictory results from the studies to date. Here, we present a longitudinal analysis of the serological responses to a SARS-CoV-2 infection following convalescence and the association with post-COVID syndrome (PCS). MATERIALS AND METHODS: A total of 237 serum samples were prospectively collected from 61 participants who had had a SARS-CoV-2 infection, which was confirmed using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). For each participant, anti-nucleocapsid (N) and anti-spike subunit 1 receptor binding domain (RBD/S1) immunoglobulin (Ig) levels were regularly determined over a period of 8 months. COVID-19-associated symptoms were assessed using a standardized questionnaire at study entry and again after 6 months. RESULTS: Antibodies were detectable in 56 of the 61 participants. No substantial decline in anti-SARS-CoV-2 pan-Ig levels was observed for the duration of the follow-up period. Antibody levels correlated positively with the disease severity, body mass index, fever, and smoking status. It was found that 46.8% of the participants suffered from PCS, with olfactory and gustatory dysfunctions being the most commonly reported symptoms. CONCLUSION: The results demonstrate stable anti-SARS-CoV-2 antibody titers and thus may indicate a long-lasting immunity. The results are in line with recently published data and provide further insight concerning asymptomatic to mildly-affected patients, the association with clinical features, and the frequency of PCS.

Specificity testing by point prevalence as a simple assessment strategy using the Roche Elecsys® anti-SARS-CoV-2 immunoassay.

BACKGROUND: The detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mandatory for the diagnosis, retrospective assessment of disease progression, and correct evaluation of the current infection situation in the population. Many such assays have been launched by various manufacturers. Unfortunately, the new US Food and Drug Administration emergency use regulations have resulted in a situation where laboratories have to perform their own validation studies but many of these laboratories do not have the biobank needed to conduct the studies. METHODS: We introduce a method that allows institutions to quickly perform a verification study in a low-prevalence infection situation. As proof of concept, we used the Roche Elecsys® anti-SARS-CoV-2 electrochemiluminescence immunoassay and an SAP-based hospital information system. The Shenzhen YHLO Biotech IgM and IgG assay targeting other surface patterns was used as a confirmatory test. RESULTS: The Roche assay demonstrated a limit of detection of 0.069 cutoff index and successfully passed the performance validation according to Clinical and Laboratory Standards Institute EP15-A3. The study population of 627 inpatients has a median age of 64 years, and approximately 13% of the group were under intensive care at the respective time point. All patients included tested negative for SARS-CoV-2 infection by quantitative reverse transcription polymerase chain reaction (cobas® 6800, Roche, Mannheim, Germany). Only one false-positive result was obtained, resulting in a specificity for the Roche Elecsys anti-SARS-CoV-2 test of 99.84% and a negative predictive value of 99.98%. CONCLUSIONS: The anonymized use of residual material enables quick evaluation of anti-SARS-CoV-2 immunoassays, as shown in this work with the Roche Elecsys assay. Comparison of the control population with economic data makes it possible to validate the sampling set and therefore to determine diagnostic specificity. By use of the approach chosen, it was shown that the Roche test achieved very good results in terms of diagnostic specificity, reproducibility, and limit of detection.

Results of the first pilot external quality assessment (EQA) scheme for anti-SARS-CoV2-antibody testing.

Objectives Assessment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection prevalence and immunity is cornerstones in the fight against COVID-19 pandemic. For pandemic control, reliable assays for the detection of anti-SARS-CoV-2 antibodies are required. This pilot external quality assessment (EQA) scheme aimed to independently assess the participants' clinical performance of anti-SARS-CoV-2 testing, to identify shortcomings in clinical practice and to evaluate the suitability of the scheme format. Methods The EQA scheme consisted of eight serum samples with variable reactivity against SARS-CoV-2 intended for the analysis of anti-SARS-CoV-2 immunoglobulin (Ig)G, IgA, and IgM antibodies. Laboratories reported: (1) results for each sample and the respective method, (2) raw data from replicate testing of each sample. Results The 16 selected pilot EQA participants reported 294 interpreted results and 796 raw data results from replicate testing. The overall error rate for the anti-SARS-CoV-2 IgG, IgA, and IgM tests was 2.7, 6.9, and 16.7%, respectively. While the overall diagnostic specificity was rated as very high, sensitivity rates between 67 and 98% indicate considerable quality differences between the manufacturers, especially for IgA and IgM. Conclusions Even the results reported by the small number of participants indicate a very heterogeneous landscape of anti-SARS-CoV-2 serological testing. Differences of available tests and the individual performance of laboratories result in a success rate of 57.1% with one laboratory succeeding for all three antibody-classes. These results are an incentive for laboratories to participate in upcoming open EQA schemes that are needed to achieve a harmonization of test results and to improve serological testing.

Results of the first external quality assessment scheme (EQA) for isolation and analysis of circulating tumour DNA (ctDNA).

BACKGROUND: Circulating tumour DNA (ctDNA) is considered to have a high potential for future management of malignancies. This pilot external quality assessment (EQA) scheme aimed to address issues of analytical quality in this new area of laboratory diagnostics. METHODS: The EQA scheme consisted of three 2-mL EDTA-plasma samples spiked with fragmented genomic DNA with a mutant allele frequency ranging from 0% to 10% dedicated to the analysis of nine known sequence variations in KRAS codon 12/13 and of BRAF V600E. Laboratories reported: (1) time elapsed for processing, (2) storage temperatures, (3) methods for extraction and quantification, (4) genotyping methodologies and (5) results. RESULTS: Specimens were sent to 42 laboratories from 10 European countries; 72.3% reported to isolate cell-free DNA (cfDNA) manually, 62.5% used the entire plasma volume for cfDNA isolation and 38.5% used >10% of cfDNA extracted for downstream genotyping. Of the methods used for quantification, PicoGreen demonstrated the lowest coefficient of variation (33.7%). For genotyping, 11 different methods were reported with the highest error rate observed for Sanger sequencing and the lowest for highly sensitive approaches like digital PCR. In total, 197 genotypes were determined with an overall error rate of 6.09%. CONCLUSIONS: This pilot EQA scheme illustrates the current variability in multiple phases of cfDNA processing and analysis of ctDNA resulting in an overall error rate of 6.09%. The areas with the greatest variance and clinical impact included specimen volume, cfDNA quantification method, and preference of genotyping platform. Regarding quality assurance, there is an urgent need for harmonisation of procedures and workflows.

Thirteen Years of an International External Quality Assessment Scheme for Genotyping: Results and Recommendations.

BACKGROUND: Suboptimal laboratory procedures resulting in genotyping errors, misdiagnosis, or incorrect reporting bear greatly on a patient's health management, therapeutic decisions made on their behalf, and ultimate outcome. Participation in external quality assessment (EQA) is a key element of quality assurance in molecular genetic diagnostics. Therefore, the Reference Institute for Bioanalytics has tried for 13 years to improve the quality of genetic testing by offering an EQA for different clinically relevant sequence variations. METHODS: Within each of the biannual EQA schemes offered, up to 18 samples of lyophilized human genomic DNA were provided for up to 50 different molecular genetic tests. Laboratories were asked to use their routine procedures for genotyping. At least 2 expert peer assessors reviewed the final returns. Data from 2002 to 2014 were evaluated. RESULTS: In total, 82 462 reported results from 812 characterized samples were evaluated. Globally, the number of participants increased each year along with the number of sequence variations offered. The error rate decreased significantly over the years with an overall error rate of 1.44%. Additionally, a decreased error rate for samples repeated over time was noted. Interestingly, the error rate showed a high difference depending on the locus analyzed and the method used. CONCLUSIONS: Based on the evaluation of this long-term EQA scheme, various recommendations can be given to improve the quality of molecular genetic testing, such as the use of 2 different methods for genotyping. Furthermore, some methods are inappropriate for analysis of certain sequence variations.