Thomas Egger , Tamara Dörr , Reto Thoma , Susanne Nigg , Lorenz Risch , Alessio Cremonesi , Pietro Vernazza , Philipp Kohler , Christian R. Kahlert
{"title":"自采干血斑点检测SARS-CoV-2核衣壳抗体敏感性低。","authors":"Thomas Egger , Tamara Dörr , Reto Thoma , Susanne Nigg , Lorenz Risch , Alessio Cremonesi , Pietro Vernazza , Philipp Kohler , Christian R. Kahlert","doi":"10.1016/j.jim.2024.113800","DOIUrl":null,"url":null,"abstract":"<div><h3>Background and aims</h3><div>Dried blood spots (DBS) have been proposed as a cost-effective surveillance method for population-wide screening of SARS-CoV-2 immunity but sensitivity of DBS based on self-collected DBS samples is unknown. To evaluate the success of vaccination strategies, it is necessary to differentiate vaccination from natural infection. Therefore, a test for antibodies against the viral nucleocapsid protein (anti-N) is desirable.</div></div><div><h3>Materials and methods</h3><div>In our prospectively followed cohort of healthcare workers (HCW) in eastern Switzerland, we assessed SARS-CoV-2-anti-N-seroprevalence using DBS on a biweekly basis from March to September 2020. Phlebotomy samples were collected in March and September and tested for anti-N-seropositivity, as well as SARS-CoV-2 spike antibodies for quantitative validation. Venous antibody testing was compared with DBS results for anti-N using the Roche Elecsys electro-chemiluminescence immunoassay.</div></div><div><h3>Results</h3><div>792 HCW (median age 38.3 years) were included, 35 (4.4 %) were SARS-CoV-2-anti-N-seropositive. Of 43 matching DBS, 25 tested positive for anti-N, accounting for a sensitivity of 58.1 % (95 %CI 43.3–71.6 %). We found a significant correlation of anti-N from DBS with results from phlebotomy samples (<em>r</em> = 0.77;<em>p</em> < 0.0001), with higher levels being associated with a higher true-positive rate. Anti-N in DBS correlated significantly with quantitatively validated anti-S obtained from serum (<em>r</em> = 0.67;<em>p</em> < 0.0001).</div></div><div><h3>Conclusion</h3><div>Although home DBS collection was feasible in a larger cohort and we found a high correlation between anti-N detection in DBS and phlebotomy samples, the sensitivity of self-collected DBS samples was significantly impaired for the Roche Elecsys anti-N assay. Therefore, we cannot recommend this method for DBS when testing from venous blood is possible.</div></div>","PeriodicalId":16000,"journal":{"name":"Journal of immunological methods","volume":"536 ","pages":"Article 113800"},"PeriodicalIF":1.6000,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Evaluation of self-collected dried blood spots for detection of SARS-CoV-2 nucleocapsid antibodies shows low sensitivity\",\"authors\":\"Thomas Egger , Tamara Dörr , Reto Thoma , Susanne Nigg , Lorenz Risch , Alessio Cremonesi , Pietro Vernazza , Philipp Kohler , Christian R. Kahlert\",\"doi\":\"10.1016/j.jim.2024.113800\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><h3>Background and aims</h3><div>Dried blood spots (DBS) have been proposed as a cost-effective surveillance method for population-wide screening of SARS-CoV-2 immunity but sensitivity of DBS based on self-collected DBS samples is unknown. To evaluate the success of vaccination strategies, it is necessary to differentiate vaccination from natural infection. Therefore, a test for antibodies against the viral nucleocapsid protein (anti-N) is desirable.</div></div><div><h3>Materials and methods</h3><div>In our prospectively followed cohort of healthcare workers (HCW) in eastern Switzerland, we assessed SARS-CoV-2-anti-N-seroprevalence using DBS on a biweekly basis from March to September 2020. Phlebotomy samples were collected in March and September and tested for anti-N-seropositivity, as well as SARS-CoV-2 spike antibodies for quantitative validation. Venous antibody testing was compared with DBS results for anti-N using the Roche Elecsys electro-chemiluminescence immunoassay.</div></div><div><h3>Results</h3><div>792 HCW (median age 38.3 years) were included, 35 (4.4 %) were SARS-CoV-2-anti-N-seropositive. Of 43 matching DBS, 25 tested positive for anti-N, accounting for a sensitivity of 58.1 % (95 %CI 43.3–71.6 %). We found a significant correlation of anti-N from DBS with results from phlebotomy samples (<em>r</em> = 0.77;<em>p</em> < 0.0001), with higher levels being associated with a higher true-positive rate. Anti-N in DBS correlated significantly with quantitatively validated anti-S obtained from serum (<em>r</em> = 0.67;<em>p</em> < 0.0001).</div></div><div><h3>Conclusion</h3><div>Although home DBS collection was feasible in a larger cohort and we found a high correlation between anti-N detection in DBS and phlebotomy samples, the sensitivity of self-collected DBS samples was significantly impaired for the Roche Elecsys anti-N assay. Therefore, we cannot recommend this method for DBS when testing from venous blood is possible.</div></div>\",\"PeriodicalId\":16000,\"journal\":{\"name\":\"Journal of immunological methods\",\"volume\":\"536 \",\"pages\":\"Article 113800\"},\"PeriodicalIF\":1.6000,\"publicationDate\":\"2025-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of immunological methods\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022175924001856\",\"RegionNum\":4,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"BIOCHEMICAL RESEARCH METHODS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of immunological methods","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022175924001856","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"BIOCHEMICAL RESEARCH METHODS","Score":null,"Total":0}
Evaluation of self-collected dried blood spots for detection of SARS-CoV-2 nucleocapsid antibodies shows low sensitivity
Background and aims
Dried blood spots (DBS) have been proposed as a cost-effective surveillance method for population-wide screening of SARS-CoV-2 immunity but sensitivity of DBS based on self-collected DBS samples is unknown. To evaluate the success of vaccination strategies, it is necessary to differentiate vaccination from natural infection. Therefore, a test for antibodies against the viral nucleocapsid protein (anti-N) is desirable.
Materials and methods
In our prospectively followed cohort of healthcare workers (HCW) in eastern Switzerland, we assessed SARS-CoV-2-anti-N-seroprevalence using DBS on a biweekly basis from March to September 2020. Phlebotomy samples were collected in March and September and tested for anti-N-seropositivity, as well as SARS-CoV-2 spike antibodies for quantitative validation. Venous antibody testing was compared with DBS results for anti-N using the Roche Elecsys electro-chemiluminescence immunoassay.
Results
792 HCW (median age 38.3 years) were included, 35 (4.4 %) were SARS-CoV-2-anti-N-seropositive. Of 43 matching DBS, 25 tested positive for anti-N, accounting for a sensitivity of 58.1 % (95 %CI 43.3–71.6 %). We found a significant correlation of anti-N from DBS with results from phlebotomy samples (r = 0.77;p < 0.0001), with higher levels being associated with a higher true-positive rate. Anti-N in DBS correlated significantly with quantitatively validated anti-S obtained from serum (r = 0.67;p < 0.0001).
Conclusion
Although home DBS collection was feasible in a larger cohort and we found a high correlation between anti-N detection in DBS and phlebotomy samples, the sensitivity of self-collected DBS samples was significantly impaired for the Roche Elecsys anti-N assay. Therefore, we cannot recommend this method for DBS when testing from venous blood is possible.
期刊介绍:
The Journal of Immunological Methods is devoted to covering techniques for: (1) Quantitating and detecting antibodies and/or antigens. (2) Purifying immunoglobulins, lymphokines and other molecules of the immune system. (3) Isolating antigens and other substances important in immunological processes. (4) Labelling antigens and antibodies. (5) Localizing antigens and/or antibodies in tissues and cells. (6) Detecting, and fractionating immunocompetent cells. (7) Assaying for cellular immunity. (8) Documenting cell-cell interactions. (9) Initiating immunity and unresponsiveness. (10) Transplanting tissues. (11) Studying items closely related to immunity such as complement, reticuloendothelial system and others. (12) Molecular techniques for studying immune cells and their receptors. (13) Imaging of the immune system. (14) Methods for production or their fragments in eukaryotic and prokaryotic cells.
In addition the journal will publish articles on novel methods for analysing the organization, structure and expression of genes for immunologically important molecules such as immunoglobulins, T cell receptors and accessory molecules involved in antigen recognition, processing and presentation. Submitted full length manuscripts should describe new methods of broad applicability to immunology and not simply the application of an established method to a particular substance - although papers describing such applications may be considered for publication as a short Technical Note. Review articles will also be published by the Journal of Immunological Methods. In general these manuscripts are by solicitation however anyone interested in submitting a review can contact the Reviews Editor and provide an outline of the proposed review.