scholarly journals Comparison of Dried Blood Spots and Venous Blood for the Detection of SARS-CoV-2 Antibodies in a Population of Nursing Home Residents

2021 ◽  
Author(s):  
Eline Meyers ◽  
Stefan Heytens ◽  
Asangwing Formukong ◽  
Hanne Vercruysse ◽  
An De Sutter ◽  
...  
Keyword(s):  
Nursing Home ◽  
General Population ◽  
Large Scale ◽  
Room Temperature ◽  
Venous Blood ◽  
Nursing Home Residents ◽  
Dried Blood Spots ◽  
Serological Tests ◽  
Finger Prick ◽  
Study Population

Since the implementation of newly developed SARS-CoV-2 vaccines in the general population, serological tests are of increasing importance. Because DBS samples can be obtained with a finger prick and can be shipped and stored at room temperature, they are optimal for use in large-scale SARS-CoV-2 serosurveillance or postauthorization vaccination studies, even in an elderly study population.

scholarly journals Comparison of dried blood spots and venous blood for the detection of SARS-CoV-2 antibodies in a population of nursing home residents

2021 ◽  
Author(s):  
Eline Meyers ◽  
Stefan Heytens ◽  
Asangwing Formukong ◽  
Hanne Vercruysse ◽  
An De Sutter ◽  
...  
Keyword(s):  
Nursing Home ◽  
Large Scale ◽  
Venous Blood ◽  
Nursing Home Residents ◽  
Dried Blood Spots ◽  
Elderly Persons ◽  
Igg Antibodies ◽  
Antibody Testing ◽  
Promising Alternative ◽  
Blood Spots

In the current SARS-CoV-2 pandemic, testing for SARS-CoV-2 specific antibodies is paramount to monitor immune responses in post-authorization vaccination and sero-epidemiology studies. However, large scale and iterative serological testing by venipuncture in older persons can be challenging. Capillary blood sampled using a finger prick and collected on protein saver cards, i.e. dried blood spots (DBS), has already proven to be a promising alternative. However, elderly persons have a reduced cutaneous microvasculature, which may affect DBS-based antibody testing. Therefore, we aimed to evaluate the performance of DBS for the detection of SARS-CoV-2 antibodies in nursing homes residents. We collected venous blood and paired Whatman and EUROIMMUN DBS from nursing home residents, and from staff as a reference population. Venous blood samples were analyzed for the presence of SARS-CoV-2 IgG antibodies using the Abbot chemiluminescent microparticle immunoassay (CMIA). DBS were analyzed by the EUROIMMUN enzyme-linked immuno sorbent assay (ELISA) for SARS-CoV-2 IgG antibodies. We performed a statistical assessment to optimize the ELISA cut-off value for the DBS using the Youden's J index. A total of 273 paired DBS-serum samples were analyzed, of which 129 were positive as assessed by the reference test. The sensitivities and specificities of DBS ranged from 95% to 97.1% and from 97.1% to 98.8%, respectively, depending on population (residents or staff) or DBS card type. These results demonstrate that DBS sampling is a valid alternative to venepuncture for the detection of SARS-CoV-2 antibodies in the elderly.

scholarly journals Magnitude, change over time, demographic characteristics and geographic distribution of excess deaths among nursing home residents during the first wave of COVID-19 in France: a nationwide cohort study

2021 ◽  
Author(s):  
Florence Canouï-Poitrine ◽  
Antoine Rachas ◽  
Martine Thomas ◽  
Laure Carcaillon-Bentata ◽  
Roméo Fontaine ◽  
...  
Keyword(s):  
Nursing Home ◽  
General Population ◽  
Excess Mortality ◽  
Nursing Home Residents ◽  
Primary Objective ◽  
List Type ◽  
Key Points ◽  
Standardized Mortality Ratios ◽  
Using Data ◽  
Excess Deaths

AbstractImportanceNursing home (NH) residents are particularly vulnerable to SARS-CoV-2 infections and coronavirus disease 2019 (COVID-19) lethality. However, excess deaths in this population have rarely been documented.ObjectivesThe primary objective was to assess the number of excess deaths among NH residents during the first wave of the COVID-19 pandemic in France. The secondary objectives were to determine the number of excess deaths as a proportion of the total excess deaths in the general population and determine whether a harvesting effect was present.DesignWe studied a cohort of 494,753 adults (as of March 1st, 2020) aged 60 and over in 6,515 NHs in mainland France. This cohort was exposed to the first wave of the COVID-19 pandemic (from March 1st to May 31st, 2020) and was compared with the corresponding, reference cohorts from 2014 to 2019 (using data from the French National Health Data System).Main outcome and measuresThe main outcome was all-cause death. Weekly excess deaths and standardized mortality ratios (SMRs) were estimated.ResultThere were 13,505 excess deaths among NH residents. Mortality increased by 43% (SMR: 1.43). The mortality excess was higher among males than among females (SMR: 1.51 and 1.38, respectively) and decreased with age (SMRs in females: 1.61 in the 60-74 age group, 1.58 for 75-84, 1.41 for 85-94, and 1.31 for 95 or over; Males: SMRs: 1.59 for 60-74, 1.69 for 75-84, 1.47 for 85-94, and 1.41 for 95 or over). We did not observe a harvesting effect (up until August 30th, 2020). By extrapolating to all NH residents nationally (N=570,003), the latter accounted for 51% of the total excess deaths in the general population (N=15,114 out of 29,563).ConclusionNH residents accounted for about half of the total excess deaths in France during the first wave of the COVID-19 pandemic. The excess death rate was higher among males than females and among younger residents than among older residents. We did not observe a harvesting effect. A real-time mortality surveillance system and the identification of individual and environmental risk factors might help to design the future model of care for older dependent adults.Key pointsDuring the first wave of the COVID-19 pandemic in France, the mortality among nursing home residents increased by 43%.Nursing home residents accounted for 51% of the total excess deaths in France.The excess mortality was higher among younger residents than among older residents.The excess mortality was higher among males than among females.We did not observe a harvesting effect during the study period (ending on August 30th, 2020, i.e., three months after the end of the first wave).

scholarly journals COVID Seroprevalence, Symptoms and Mortality During the First Wave of SARS-CoV-2 in Canada

2021 ◽  
Author(s):  
◽  
Prabhat Jha
Keyword(s):  
Nursing Home ◽  
Nursing Homes ◽  
Nursing Home Residents ◽  
High Sensitivity ◽  
High Specificity ◽  
The Elderly ◽  
Dried Blood Spots ◽  
Mortality Data ◽  
Infection Prevalence ◽  
Antibody Testing

Background: Efforts to stem the SARS-CoV-2 pandemic in Canada can benefit from direct understanding of the prevalence, infection fatality rates (IFRs), and information on asymptomatic infection. Methods: We surveyed a representative sample of 19,994 adult Canadians about COVID symptoms and analyzed IgG antibodies against SARS-CoV-2 from self-collected dried blood spots (DBS) in 8,967 adults. A sensitive and specific chemiluminescence ELISA detected IgG to the spike trimer. We compared seroprevalence to deaths to establish IFRs and used mortality data to estimate infection levels in nursing home residents. Results: The best estimate (high specificity) of adult seroprevalence nationally is 1.7%, but as high as 3.5% (high sensitivity) depending on assay cut-offs. The highest prevalence was in Ontario (2.4-3.9%) and in younger adults aged 18-39 years (2.5-4.4%). Based on mortality, we estimated 13-17% of nursing home residents became infected. The first viral wave infected 0.54-1.08 million adult Canadians, half of whom were <40 years old. The IFR outside nursing homes was 0.20-0.40%, but the COVID mortality rate in nursing home residents was >70 times higher than that in comparably-aged adults living in the community. Seropositivity correlated with COVID symptoms, particularly during March. Asymptomatic adults constituted about a quarter of definite seropositives, with a greater proportion in the elderly. Interpretation: Canada had relatively low infection prevalence and low IFRs in the community, but not in nursing homes, during the first viral wave. Self-collected DBS for antibody testing is a practicable strategy to monitor the ongoing second viral wave and, eventually, vaccine-induced immunity among Canadian adults.

scholarly journals Self-sampling of capillary blood for serological testing of SARS-CoV-2 by COVID-19 IgG ELISA

2020 ◽  
Author(s):  
Lottie Brown ◽  
Rachel Louise Byrne ◽  
Alice Fraser ◽  
Sophie I Owen ◽  
Ana I Cubas Atienzar ◽  
...  
Keyword(s):  
Large Scale ◽  
Venous Blood ◽  
Dried Blood Spots ◽  
Capillary Blood ◽  
Blood Collection ◽  
Serological Testing ◽  
Perfect Agreement ◽  
Blood Samples ◽  
Large Scale Testing ◽  
Feasible Alternative

Serological testing is emerging as a powerful tool to progress our understanding of COVID-19 exposure, transmission and immune response. Large-scale testing is limited by the need for in-person blood collection by staff trained in venepuncture. Capillary blood self-sampling and postage to laboratories for analysis could provide a reliable alternative. Two-hundred and nine matched venous and capillary blood samples were obtained from thirty nine participants and analysed using a COVID-19 IgG ELISA to detect antibodies against SARS-CoV-2. Thirty seven out of thirty eight participants were able to self-collect an adequate sample of capillary blood (≥50 μl). Using plasma from venous blood collected in lithium heparin as the reference standard, matched capillary blood samples, collected in lithium heparin-treated tubes and on filter paper as dried blood spots, achieved a Cohen′s kappa coefficient of >0.88 (near-perfect agreement). Storage of capillary blood at room temperature for up to 7 days post sampling did not affect concordance. Our results indicate that capillary blood self-sampling is a reliable and feasible alternative to venepuncture for serological assessment in COVID-19.

scholarly journals Remote fingerstick blood collection for SARS-CoV-2 antibody testing

2020 ◽  
Author(s):  
Wilfredo F. Garcia-Beltran ◽  
Tyler E. Miller ◽  
Grace Kirkpatrick ◽  
Andrea Nixon ◽  
Michael G. Astudillo ◽  
...  
Keyword(s):  
High Throughput ◽  
Large Scale ◽  
Dynamic Range ◽  
Rapid Development ◽  
Venous Blood ◽  
Blood Collection ◽  
Antibody Assay ◽  
Serum Samples ◽  
Blood Draw ◽  
Serological Tests

ABSTACT The rapid worldwide spread of severe acute respiratory system coronavirus 2 (SARSCoV-2) infection has propelled the rapid development of serological tests that can detect anti-SARS-CoV-2 antibodies. These have been used for studying the prevalence and spread of infection in different populations, helping establish a recent diagnosis of coronavirus disease 2019 (COVID-19), and will likely be used to confirm humoral immunity after infection or vaccination. However, nearly all lab-based high-throughput SARS-CoV-2 serological assays require a serum sample from venous blood draw, limiting their applications and scalability. Here, we present a method that enables large scale SARS-CoV-2 serological studies by combining self or office collection of fingerprick blood with a volumetric absorptive microsampling device (Mitra, Neoteryx, LLC) with a high-throughput electrochemiluminescence-based SARS-CoV-2 total antibody assay (Roche Elecsys, Roche Diagnostics, Inc.) that is emergency use authorization (EUA) approved for use on serum samples and widely used by clinical laboratories around the world. We found that the Roche Elecsys assay has a high dynamic range that allows for accurate detection of SARS-CoV-2 antibodies in serum samples diluted 1:20 as well as contrived dried blood extracts. Extracts of dried blood from Mitra devices acquired in a community seroprevalence study showed near identical sensitivity and specificity in detection of SARS-CoV-2 antibodies as compared to neat sera using predefined thresholds for each specimen type. Overall, this study affirms the use of Mitra dried blood collection device with the Roche Elecsys SARS-CoV-2 total antibody assay for remote or at-home testing as well as large-scale community seroprevalence studies.

scholarly journals A serological assay to detect SARS-CoV-2 antibodies in at-home collected finger-prick dried blood spots

2020 ◽  
Author(s):  
Donna Grace Karp ◽  
Kenneth Danh ◽  
David Seftel ◽  
Peter Robinson ◽  
Cheng-ting Tsai
Keyword(s):  
Healthcare Worker ◽  
Large Scale ◽  
Health Care Systems ◽  
Dried Blood Spots ◽  
Sample Collection ◽  
Finger Prick ◽  
Care Systems ◽  
Hard To Reach Populations ◽  
Development And Validation ◽  
At Home

Accurate surveillance of coronavirus disease 2019 (COVID-19) incidence requires large-scale testing of the population. Current testing methods require in-person collection of biospecimens by a healthcare worker, limiting access of individuals who do not have access to testing facilities while placing both the patient and healthcare worker at risk of exposure to infection. We report the development and validation of a at-home finger-prick dried blood spot collection kit and an analysis method. We demonstrated 100% sensitivity and specificity using at-home collected specimens across the US. Such methods may facilitate the conduct of unbiased serosurveys within hard to reach populations and help reduce the sample collection burden of serological testing on both health care systems and individuals alike.

scholarly journals An affordable anti-SARS-COV-2 spike protein ELISA test for early detection of IgG seroconversion suited for large-scale surveillance studies in low-income countries

2020 ◽  
Author(s):  
Renata G. F. Alvim ◽  
Tulio M. Lima ◽  
Danielle A. S. Rodrigues ◽  
Federico F. Marsili ◽  
Vicente B. T. Bozza ◽  
...  
Keyword(s):  
Low Income ◽  
Large Scale ◽  
Low Cost ◽  
Venous Blood ◽  
Hek293 Cells ◽  
Epidemiological Surveillance ◽  
Low Income Countries ◽  
Serological Tests ◽  
S Protein ◽  
Surveillance Studies

AbstractBackgroundAccurate serological tests are essential tools to allow adequate monitoring and control of COVID-19 spread. Production of a low-cost and high-quality recombinant viral antigen can enable the development of reliable and affordable serological assays, which are urgently needed to facilitate epidemiological surveillance studies in low-income economies.MethodsTrimeric SARS-COV-2 spike (S) protein was produced in serum-free, suspension-adapted HEK293 cells. Highly purified S protein was used to develop an ELISA, named S-UFRJ test. It was standardized to work with different types of samples: (i) plasma or serum from venous blood samples; (ii) eluates from dried blood spots (DBS) obtained by collecting blood drops from finger prick.FindingsWe developed a cost-effective, scalable technology to produce S protein based on its stable expression in HEK293 cells. Using this recombinant antigen we presented a workflow for test development in the setting of a pandemic, starting from limited amounts of samples up to reaching final validation with hundreds of samples. Test specificity was determined to be 98.6%, whereas sensitivity was 95% for samples collected 11 or more days after symptoms onset. A ROC analysis allowed optimizing the cut-off and confirming the high accuracy of the test. Endpoint titers were shown to correlate with virus neutralization assessed as PRNT90. There was excellent agreement between plasma and DBS samples, significantly simplifying sample collection, storing and shipping. An overall cost estimate revealed that final retail price could be in the range of one US dollar.InterpretationThe S-UFRJ assay developed herein meets the quality requirements of high sensitivity and specificity. The low cost and the use of mailable DBS samples allow for serological surveillance of populations regardless of geographical and socio-economic aspects, with special relevance for public health policy actions in low-income countries.FundingCTG, Senai DN/CETIQT, FAPERJ, CNPq, CAPES and Instituto Serrapilheira.

scholarly journals Parvovirus B19 in Croatia: A Large-Scale Seroprevalence Study

Medicina ◽  
2021 ◽  
Vol 57 (11) ◽  
pp. 1279
Author(s):  
Tatjana Vilibic-Cavlek ◽  
Irena Tabain ◽  
Branko Kolaric ◽  
Klara Mihulja ◽  
Lana Blazevic ◽  
...  
Keyword(s):  
General Population ◽  
Large Scale ◽  
Parvovirus B19 ◽  
Adult Population ◽  
Hemodialysis Patients ◽  
Enzyme Linked Immunosorbent Assay ◽  
Age Group ◽  
Igg Antibodies ◽  
Serological Tests ◽  
Recent Infection

Background and Objectives: Seroepidemiological studies indicate that parvovirus B19 circulates in all areas of the world, although with some differences. The aim of this study is to analyze the seroprevalence of parvovirus B19 in the Croatian population. Materials and Methods: From 2010 to 2021, 1538 serum samples from different populations were tested for the presence of parvovirus B19 IgM/IgG antibodies. Serological tests were performed using a commercial enzyme-linked immunosorbent assay. Results: IgG antibodies were detected in 986/64.1% of participants with differences (p < 0.001) among the following population groups: 42.4% of children and adolescents, 67.1% of the adult general population, 66.7% of hemodialysis patients, and 65.6% of liver transplant recipients. Seroprevalence increased with age, from 30.0% in the 6 months–9 years age group to 69.0% in the 40–49 years age group, and remained stable thereafter (68.8–73.3%). There was no difference in the seropositivity among males (66.1%) and females (63.1%), as well as the place of residence (suburban/rural 63.9%, urban 64.1%). IgM antibodies (current/recent infection) were found in 61/4.0% of participants with the highest seropositivity in the youngest age group (11.1%). In pregnant women, seroprevalence was higher in women with an unfavorable obstetric history compared with a normal pregnancy (IgG 71.0% vs. 62.6%; IgM 6.5% vs. 2.4%), but these differences were not significant. Logistic regression showed that the adult population had almost three times higher risk of IgG seropositivity compared to children/adolescents (general population OR = 2.777, 95% CI = 2.023–3.812; hemodialysis patients OR = 2.586, 95% CI = 1.531–4.367; and transplant patients OR = 2.717, 95% CI = 1.604–4.603). A one-year increase in age increased the risk of IgG seroprevalence (OR = 1.017; 95% CI = 1.011–1.022). Conclusions: Older age was the main risk factor for IgG seropositivity. Hemodialysis and organ transplantation seem unrelated to the increased parvovirus B19 seroprevalence. The role of parvovirus B19 in the etiology of TORCH infections needs to be studied further.

scholarly journals Measurement of the alcohol biomarker phosphatidylethanol (PEth) in dried blood spots and venous blood—importance of inhibition of post-sampling formation from ethanol

2021 ◽  
Author(s):  
Olof Beck ◽  
Maria Mellring ◽  
Christian Löwbeer ◽  
Sabina Seferaj ◽  
Anders Helander
Keyword(s):  
Filter Paper ◽  
Whole Blood ◽  
Room Temperature ◽  
Venous Blood ◽  
Dried Blood Spots ◽  
Blood Samples ◽  
Ethanol Formation ◽  
Alcohol Biomarker ◽  
Blood Specimens ◽  
Blood Spot

AbstractPhosphatidylethanol (PEth) is a group of phospholipids formed in cell membranes following alcohol consumption by action of the enzyme phospholipase D (PLD). PEth measurement in whole blood samples is established as a specific alcohol biomarker with clinical and forensic applications. However, in blood specimens containing ethanol, formation of PEth may continue after sampling leading to falsely elevated concentrations. This study evaluated the use of dried blood spot (DBS) and microsampling specimens to avoid post-sampling formation of PEth. Filter paper cards and three commercial devices for volumetric microsampling of finger-pricked blood were assessed, using PEth-negative and PEth-positive whole blood fortified with 2 g/L ethanol. PEth (16:0/18:1) was measured by LC–MS/MS. Post-sampling formation of PEth occurred in wet blood and in the volumetric devices, but not filter paper cards, when stored at room temperature for 48 h. Addition of an inhibitor of PLD, sodium metavanadate (NaVO3), eliminated post-sampling formation during storage and drying. In conclusion, the present study confirmed previous observations that PEth can be formed in blood samples after collection, if the specimen contains ethanol. The results further demonstrated that post-sampling formation of PEth from ethanol also occurred with commercial devices for volumetric dried blood microsampling. In order for a PEth result not to be questioned, it is recommended to use a PLD inhibitor, whether venous blood is collected in a vacutainer tube or finger-pricked blood is obtained using devices for dried blood microsampling. Graphical abstract

Sign in / Sign up

Export Citation Format

Share Document