scholarly journals Sensitive detection of SARS-CoV-2-specific-antibodies in dried blood spot samples

2020 ◽  
Author(s):  
Gabriella L. Morley ◽  
Stephen Taylor ◽  
Sian Jossi ◽  
Marisol Perez-Toledo ◽  
Sian E. Faustini ◽  
...  
Keyword(s):  
Sampling Method ◽  
Dried Blood Spot ◽  
Serological Testing ◽  
Spike Glycoprotein ◽  
Serum Samples ◽  
Perfect Agreement ◽  
Specific Antibodies ◽  
Antibody Levels ◽  
Matched Samples ◽  
Blood Spot

AbstractImportancePopulation-wide serological testing is an essential component in understanding the COVID-19 pandemic. The logistical challenges of undertaking widespread serological testing could be eased through use of a reliable dried blood spot (DBS) sampling method.ObjectiveTo validate the use of dried blood spot sampling for the detection of SARS-CoV-2-specific antibodies.Design, setting and participantsEighty-seven matched DBS and serum samples were obtained from eighty individuals, including thirty-one who were previously PCR-positive for SARS-CoV-2. DBS eluates and sera were used in an ELISA to detect antibodies to the viral spike protein.ResultsSpecific anti-SARS-Cov-2 spike glycoprotein antibodies were detectable in both serum and DBS eluate and there was a significant correlation between the antibody levels detected in matched samples (r = 0.96, p<0.0001). Using serum as the gold standard in the assay, matched DBS samples achieved a Cohen’s kappa coefficient of 0.975 (near-perfect agreement), a sensitivity of 98.1% and specificity of 100%, for detecting anti-spike glycoprotein antibodies.Conclusions and relevanceEluates from DBS samples are a reliable and reproducible source of antibodies to be used for the detection of SARS-CoV-2-specific antibodies. The use of DBS sampling could complement the use of venepuncture in the immunosurveillance of COVID-19 in both low and high income settings.

scholarly journals Monitoring of SARS-CoV-2 Antibodies Using Dried Blood Spot for At-Home Collection

2021 ◽  
Author(s):  
Peyton K Miesse ◽  
Bradley B Collier ◽  
Russell P Grant
Keyword(s):  
Dried Blood Spot ◽  
Serological Testing ◽  
Serum Samples ◽  
Antibody Levels ◽  
Blood Spot ◽  
At Home

The utilization of vaccines to fight the spread of SARS-CoV-2 has led to a growing need for expansive serological testing. To address this, an EUA approved immunoassay for detection of antibodies to SARS-CoV-2 in venous serum samples was investigated for use with dried blood spot (DBS) samples. Results from self-collected DBS samples demonstrated a 98.1% categorical agreement to venous serum with a correlation (R) of 0.9600 while professionally collected DBS samples demonstrated a categorical agreement of 100.0% with a correlation of 0.9888 to venous serum. Additional studies were performed to stress different aspects of at-home DBS collection, including shipping stability, effects of interferences, and other sample-specific robustness studies. These studies demonstrated a categorical agreement of at least 95.0% and a mean bias less than ±20.0%. Furthermore, the ability to track antibody levels following vaccination with the BioNTech/Pfizer vaccine was demonstrated with serial self-collected DBS samples from pre-dose (Day 0) out to 19 weeks.

scholarly journals 151. The Use of Dried Blood Spot Cards to Assess Serologic Responses of Individuals Vaccinated Against Measles, Hepatitis A, Tetanus, Influenza and Varicella Zoster

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S205-S206
Author(s):  
Janine R Danko ◽  
Robert Taylor ◽  
Brian Reinhardt ◽  
Nora L Watson ◽  
Taylor Banks
Keyword(s):  
Influenza A ◽  
Hepatitis A ◽  
Natural Infection ◽  
Dried Blood Spot ◽  
Serum Samples ◽  
Varicella Zoster ◽  
Influenza A H1n1 ◽  
Highly Correlated ◽  
Antibody Levels ◽  
Blood Spot

Abstract Background Traditional blood sampling by venipuncture is cumbersome and expensive. Dried Blood Spot (DBS) sampling is desirable because of its ease of sample collection, transportation and storage. It has been used in clinical diagnosis but not been thoroughly studied for the potential use to assess the immune status of individuals following natural infection or preventive vaccination. The goal of this study is to compare DBS to traditional blood samplings in detection of antibodies in individuals vaccinated against measles, hepatitis A, tetanus, influenza and varicella zoster. Methods Blood from 220 vaccinated individuals were collected by venipuncture into serum separation tubes and by fingerstick onto Whatman 903® protein saver cards. ELISA was used to test DBS eluates and serum samples for antibodies against measles, varicella, tetanus and hepatitis A. Sensitivities, specificities, and correlation coefficients were evaluated to compare optical density (OD) values of paired serum and DBS samples. Hemagglutinin inhibition (HAI) and microneutralization assay (MNA) were used to determine anti-influenza antibody in serum and DBS samples. The long term stability of DBS samples at different temperatures was assessed using simulated immune measles blood. Results DBS OD was highly correlated with serum OD for antibodies to measles (r = 0.93), varicella (r = 0.82), and tetanus (r = 0.91) (Fig.1). Sensitivities of DBS OD ranged from 86–99% and specificities ranged from 96–100% using cut-offs established by each assay. By contrast, the hepatitis A data showed a low sensitivity (31%) and a weak correlation (r = 0.14) between DBS and serum samples. HAI and MNA assays showed a broad range of anti-influenza A (H1N1 and H3N1) antibody titers in serum samples but failed to detect the antibodies in DBS eluates. The stability data indicated that DBS samples were stable for 4 weeks when stored at room temperature and for 6 months at 4°C (Fig. 2). Figure 1. Correlation of antibody levels detected by DBS sampling to the antibody levels detected by serum sampling for measles, hepatitis A, tetanus and varicella zoster. Figure 2. Stability of the blood samples on DBS cards stored under various temperatures for 25 weeks as measured by the titers of anti-measles antibody (IgG) at various time points. Conclusion DBS sampling was sensitive, specific, and highly correlated with traditional venipuncture sampling in detection of antibodies against measles, tetanus and varicella zoster, but not hepatitis A and influenza. Thus, the success of using DBS sampling to assess the antibody levels in immunized individuals may be dependent on the pathogens and the type of assay used. Disclosures All Authors: No reported disclosures

scholarly journals PEDV Infection Generates Conformation-Specific Antibodies That Can Be Effectively Detected by a Cell-Based ELISA

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 303
Author(s):  
Wei-Ting Hsu ◽  
Chia-Yu Chang ◽  
Chih-Hsuan Tsai ◽  
Sung-Chan Wei ◽  
Huei-Ru Lo ◽  
...  
Keyword(s):  
Recombinant Baculovirus ◽  
Immunocytochemical Staining ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Perfect Agreement ◽  
Specific Antibodies ◽  
Diarrhea Virus ◽  
Serological Studies ◽  
A Cell ◽  
Infected Insect

Porcine epidemic diarrhea virus (PEDV) is a coronavirus that causes serious and highly contagious enteric disease in swine worldwide. In this study, we constructed a recombinant baculovirus (S-Bac) expressing full-length spike protein of the virulent epidemic genotype 2b (G2b) PEDV strain for serological studies of infected pigs. We found that most spike-specific antibodies produced upon PEDV infection in pigs are conformation-specific and they could be detected on S-Bac-infected insect cells by immunofluorescent assay, but they were insensitive to Western blot analysis, the typical method for antiserum analysis. These results indicated that spike conformation is crucial for serum recognition. Since it is difficult to purify trimeric spike membrane protein for conventional enzyme-linked immunosorbent assay (ELISA), we used S-Bac to generate a novel cell-based ELISA for convenient PEDV detection. We analyzed 100 pig serum samples, and our cell-based ELISA exhibited a sensitivity of 100%, a specificity of 97%, and almost perfect agreement [Cohen’s kappa coefficient value (κ) = 0.98] with immunocytochemical staining results. Our cell-based ELISA rapidly presented antigen for proper detection of conformation-specific antibodies, making PEDV detection more convenient, and it will be useful for detecting many viral diseases in the future.

scholarly journals Dried Blood Spot Analysis Suitable for Therapeutic Drug Monitoring of Voriconazole, Fluconazole, and Posaconazole

2013 ◽  
Vol 57 (10) ◽  
pp. 4999-5004 ◽  
Author(s):  
Kim C. M. van der Elst ◽  
Lambert F. R. Span ◽  
Kai van Hateren ◽  
Karin M. Vermeulen ◽  
Tjip S. van der Werf ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
Sampling Method ◽  
Fungal Infections ◽  
Venous Blood ◽  
Blood Sampling ◽  
Dried Blood Spot ◽  
Therapeutic Drug ◽  
Venous Blood Sampling ◽  
Blood Spot

ABSTRACTInvasive aspergillosis and candidemia are important causes of morbidity and mortality in immunocompromised and critically ill patients. The triazoles voriconazole, fluconazole, and posaconazole are widely used for the treatment and prophylaxis of these fungal infections. Due to the variability of the pharmacokinetics of the triazoles among and within individual patients, therapeutic drug monitoring is important for optimizing the efficacy and safety of antifungal treatment. A dried blood spot (DBS) analysis was developed and was clinically validated for voriconazole, fluconazole, and posaconazole in 28 patients. Furthermore, a questionnaire was administered to evaluate the patients' opinions of the sampling method. The DBS analytical method showed linearity over the concentration range measured for all triazoles. Results for accuracy and precision were within accepted ranges; samples were stable at room temperature for at least 12 days; and different hematocrit values and blood spot volumes had no significant influence. The ratio of the drug concentration in DBS samples to that in plasma was 1.0 for voriconazole and fluconazole and 0.9 for posaconazole. Sixty percent of the patients preferred DBS analysis as a sampling method; 15% preferred venous blood sampling; and 25% had no preferred method. There was significantly less perception of pain with the DBS sampling method (P= 0.021). In conclusion, DBS analysis is a reliable alternative to venous blood sampling and can be used for therapeutic drug monitoring of voriconazole, fluconazole, and posaconazole. Patients were satisfied with DBS sampling and had less pain than with venous sampling. Most patients preferred DBS sampling to venous blood sampling.

scholarly journals High seroprevalence for SARS-CoV-2 among household members of essential workers detected using a dried blood spot assay

2020 ◽  
Author(s):  
Thomas W. McDade ◽  
Elizabeth M. McNally ◽  
Aaron S. Zelikovich ◽  
Richard D’Aquila ◽  
Brian Mustanski ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Venous Blood ◽  
Binding Domain ◽  
Spike Protein ◽  
Dried Blood Spot ◽  
Receptor Binding Domain ◽  
Serological Testing ◽  
Igg Antibodies ◽  
Household Members ◽  
Blood Spot

AbstractObjectiveSerological testing is needed to investigate the extent of transmission of SARS-CoV-2 from front-line essential workers to their household members. However, the requirement for serum/plasma limits serological testing to clinical settings where it is feasible to collect and process venous blood. To address this problem we developed a serological test for SARS-CoV-2 IgG antibodies that requires only a single drop of finger stick capillary whole blood, collected in the home and dried on filter paper (dried blood spot, DBS).MethodsAn ELISA to the receptor binding domain of the SARS-CoV-2 spike protein was optimized to quantify IgG antibodies in DBS. Samples were self-collected from a community sample of 232 participants enriched with health care workers, including 30 known COVID-19 cases and their household members.ResultsAmong 30 individuals sharing a household with a virus-confirmed case of COVID-19, 80% were seropositive. Of 202 community individuals without prior confirmed acute COVID-19 diagnoses, 36% were seropositive. Of documented convalescent COVID-19 cases from the community, 29 of 30 (97%) were seropositive for IgG antibodies to the receptor binding domain.ConclusionDBS ELISA provides a minimally-invasive alternative to venous blood collection. Early analysis suggests a high rate of transmission among household members. High rates of seroconversion were also noted following recovery from infection. Serological testing for SARSCoV-2 IgG antibodies in DBS samples can facilitate seroprevalence assessment in community settings to address epidemiological questions, monitor duration of antibody responses, and assess if antibodies against the spike protein correlate with protection from reinfection.

scholarly journals Enzyme-linked immunosorbent assays for the measurement of specific antibodies in experimentally induced ovine toxoplasmosis

1988 ◽  
Vol 100 (2) ◽  
pp. 205-212 ◽  
Author(s):  
R. A. Payne ◽  
D. H. M. Joynson ◽  
A. J. Wilsmore
Keyword(s):  
Toxoplasma Gondii ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Capture Assay ◽  
Previous Infection ◽  
Specific Igg ◽  
Immunosorbent Assays ◽  
Antibody Class ◽  
Antibody Levels ◽  
Indirect Assay

SUMMARYTachyzoitcs of the RH strain of Toxoplasma gondii were inoculated intravenously into sheep following which serum samples were collected at approximately weekly intervals for 9 months. The sera were examined by the toxoplasma dye test and two enzymc-linkcd immunosorbent assays (ELISA) specifically developed for investigations of ovine toxoplasmosis. One was an antibody class capture assay for the detection of anti-toxoplasma specific IgM, the other an indirect assay which detected anti-toxoplasma IgG.Some of the sheep had antibodies to toxoplasma prior to inoculation but none had specific IgM. Sera collected 17 days after inoculation showed that all had raised specific antibody levels but the only sheep that produced specific antitoxoplasma IgM were those that were initially without any antibody. Specific IgM could be detected in all these particular sheep for at least 1 month after infection and up to 3 months in some. Specific IgG persisted at high levels for at least 3 months and could still be detected at moderate levels for at least 9 months. The ELISA methods described are simple to perform and could clearly distinguish between previous infection and this experimental infection with Toxoplasma gondii.

scholarly journals Volumetric absorptive microsampling and dried blood spot microsampling vs. conventional venous sampling for tacrolimus trough concentration monitoring

2020 ◽  
Vol 58 (10) ◽  
pp. 1687-1695 ◽  
Author(s):  
Herman Veenhof ◽  
Remco A. Koster ◽  
Lenneke A.T. Junier ◽  
Stefan P. Berger ◽  
Stephan J.L. Bakker ◽  
...  
Keyword(s):  
Trough Concentration ◽  
Method Comparison ◽  
Dried Blood Spot ◽  
Blood Concentrations ◽  
Transplant Patients ◽  
Significant Difference ◽  
Tacrolimus Trough Concentration ◽  
Matched Samples ◽  
Blood Spot ◽  
Volumetric Absorptive Microsampling

AbstractObjectivesMonitoring tacrolimus blood concentrations is important for preventing allograft rejection in transplant patients. Our hospital offers dried blood spot (DBS) sampling, giving patients the opportunity to sample a drop of blood from a fingerprick at home, which can be sent to the laboratory by mail. In this study, both a volumetric absorptive microsampling (VAMS) device and DBS sampling were compared to venous whole blood (WB) sampling.MethodsA total of 130 matched fingerprick VAMS, fingerprick DBS and venous WB samples were obtained from 107 different kidney transplant patients by trained phlebotomists for method comparison using Passing-Bablok regression. Bias was assessed using Bland-Altman. A multidisciplinary team pre-defined an acceptance limit requiring >80% of all matched samples within 15% of the mean of both samples. Sampling quality was evaluated for both VAMS and DBS samples.Results32.3% of the VAMS samples and 6.2% of the DBS samples were of insufficient quality, leading to 88 matched samples fit for analysis. Passing-Bablok regression showed a significant difference between VAMS and WB, with a slope of 0.88 (95% CI 0.81–0.97) but not for DBS (slope 1.00; 95% CI 0.95–1.04). Both VAMS (after correction for the slope) and DBS showed no significant bias in Bland-Altman analysis. For VAMS and DBS, the acceptance limit was met for 83.0% and 96.6% of the samples, respectively.ConclusionsVAMS sampling can replace WB sampling for tacrolimus trough concentration monitoring, but VAMS sampling is currently inferior to DBS sampling, both regarding sample quality and agreement with WB tacrolimus concentrations.

scholarly journals Performance of Immunoglobulin G Serology on Finger Prick Capillary Dried Blood Spot Samples to Measure SARS-CoV-2 Humoral Immunogenicity

2021 ◽  
Author(s):  
Aidan M Nikiforuk ◽  
Brynn McMillan ◽  
Sofia R Bartlett ◽  
Ana Citlali Marquez ◽  
Tamara Pidduck ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Predictive Value ◽  
Vaccine Coverage ◽  
Characteristic Curve ◽  
Dried Blood Spot ◽  
Serum Samples ◽  
Meso Scale Discovery ◽  
Cross Sectional ◽  
Finger Prick ◽  
Blood Spot

Abstract: Importance: Measuring humoral immunogenicity of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccines and finding population-level correlates of protection against coronavirus disease (COVID-19) presents an immediate challenge to public health practitioners. Objective: To study the diagnostic accuracy and predictive value of finger prick capillary dried blood spot (DBS) samples tested using an anti-immunoglobulin G (IgG) serology assay to measure SARS-CoV-2 seropositivity and the humoral immunogenicity of COVID-19 vaccination. Design, Setting and Participants: This cross-sectional study enrolled participants (n= 644) who had paired DBS and serum samples collected by finger prick and venipuncture, respectively, in British Columbia, Canada between January 12th, 2020 and May 21st, 2021. Samples were tested by a multiplex electrochemiluminescence assay for SARS-CoV-2 anti-Spike (S), -Nucleocapsid (N) and -receptor binding domain (RBD) IgG reactivity using a Meso Scale Discovery (MSD) platform. Additionally, unpaired DBS samples (n= 6,706) that were collected in the province during the same time period were included for analysis of SARS-CoV-2 anti-N IgG reactivity. Exposure: Collection of a capillary DBS by finger prick alone or paired with serum by venipuncture. Outcome: Humoral immune response to SARS-CoV-2 measured by detection of anti-S, -N or -RBD IgG. Results: In comparison to a paired-serum reference, DBS samples possessed a sensitivity of 80% (95% CI: 61%-91%) and specificity of 97% (95% CI: 95%-98%). Receiver operator characteristic curve analysis (ROC) found that participant DBS samples tested for anti-SARS-CoV-2 IgG by MSD V-PLEX COVID-19 Coronavirus Panel 2 assay accurately classify SARS-CoV-2 seroconversion at an 88% percent rate, AUC= 88% (95% CI: 81%-96%). Modelling found that a DBS-based testing approach has a high positive predictive value (PPV) (98% [95% CI: 98%-99%]) in a theoretical population with seventy-five percent COVID-19 vaccine coverage. At lower vaccine coverages of fifteen and forty-five percent, the test's PPV decreased and the negative predictive value increased. Conclusion: We demonstrate that DBS samples, when tested using an electrochemiluminescence assay, provide a valid alternative to traditional venipuncture and should be considered to reliably detect SARS-CoV-2 seropositivity.

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