ABSTRACT
Background and Objectives: A sufficient supply of safe, high-quality blood components for transfusion is essential to the healthcare system in Germany. The requirements for the current reporting system are laid down in the German Transfusion Act. The present work elaborates on the advantages and limitations of the current reporting system and investigates the feasibility of a pilot project that collects specific data on blood supply based on weekly reports. Materials and Methods: Selected data on blood collection and supply from 2009 to 2021 derived from the §21 German Transfusion Act database were examined. In addition, a pilot study over a period of 12 months was conducted on a voluntary basis. The number of red blood cell (RBC) concentrates was documented and stock availability was calculated weekly. Results: From 2009 to 2021, the annual number of RBC concentrates decreased from 4.68 to 3.43 million, the per capita distribution decreased from 58 to 41 RBC concentrates per 1,000 inhabitants. These figures did not change significantly during the COVID-19 pandemic. The data of the 1-year pilot project represented 77% of the released RBC concentrates in Germany. Percentage share of O RhD positive RBC concentrates fluctuated between 35% and 22% and for O RhD negative concentrates between 17% and 5%. The availability of O RhD positive RBC concentrate stocks varied between 2.1 and 7.6 days. Conclusion: The data presented shows a decrease in annual RBC concentrate sales over an 11-year period and no further change over the past 2 years. A weekly monitoring of blood components detects acute problems in RBC provision and supply. Close monitoring seems helpful but should be combined with a nationwide supply strategy.
ABSTRACT
A number of seroassays are available for SARS-CoV-2 testing; yet, head-to-head evaluations of different testing principles are limited, especially using raw values rather than categorical data. In addition, identifying correlates of protection is of utmost importance, and comparisons of available testing systems with functional assays, such as direct viral neutralisation, are needed.We analysed 6658 samples consisting of true-positives (n=193), true-negatives (n=1091), and specimens of unknown status (n=5374). For primary testing, we used Euroimmun-Anti-SARS-CoV-2-ELISA-IgA/IgG and Roche-Elecsys-Anti-SARS-CoV-2. Subsequently virus-neutralisation, GeneScriptcPass, VIRAMED-SARS-CoV-2-ViraChip, and Mikrogen-recomLine-SARS-CoV-2-IgG were applied for confirmatory testing. Statistical modelling generated optimised assay cut-off thresholds. Sensitivity of Euroimmun-anti-S1-IgA was 64.8%, specificity 93.3% (manufacturer's cut-off); for Euroimmun-anti-S1-IgG, sensitivity was 77.2/79.8% (manufacturer's/optimised cut-offs), specificity 98.0/97.8%; Roche-anti-N sensitivity was 85.5/88.6%, specificity 99.8/99.7%. In true-positives, mean and median Euroimmun-anti-S1-IgA and -IgG titres decreased 30/90 days after RT-PCR-positivity, Roche-anti-N titres decreased significantly later. Virus-neutralisation was 80.6% sensitive, 100.0% specific (≥1:5 dilution). Neutralisation surrogate tests (GeneScriptcPass, Mikrogen-recomLine-RBD) were >94.9% sensitive and >98.1% specific. Optimised cut-offs improved test performances of several tests. Confirmatory testing with virus-neutralisation might be complemented with GeneScriptcPassTM or recomLine-RBD for certain applications. Head-to-head comparisons given here aim to contribute to the refinement of testing strategies for individual and public health use.