scholarly journals Validation of a combined ELISA to detect IgG, IgA and IgM antibody responses to SARS-CoV-2 in mild or moderate non-hospitalised patients

2020 ◽  
Author(s):  
A M Cook ◽  
S E Faustini ◽  
L J Williams ◽  
A F Cunningham ◽  
M T Drayson ◽  
...  
Keyword(s):  
Dried Blood Spots ◽  
Antibody Responses ◽  
Clinical Samples ◽  
Serum Samples ◽  
Blood Spots ◽  
Moderate Disease ◽  
Hospitalised Patients ◽  
Supplementary Material ◽  
Human Viruses ◽  
Targeted Detection

AbstractBackgroundFrequently SARS-CoV-2 results in mild or moderate disease with potentially lower concentrations of antibodies compared to those that are hospitalised. Here, we validated an ELISA using SARS-CoV-2 trimeric spike glycoprotein, with targeted detection of IgG, IgA and IgM (IgGAM) using serum and dried blood spots (DBS) from adults with mild or moderate disease.MethodsTargeting the SARS-CoV-2 trimeric spike, a combined anti-IgG, IgA and IgM serology ELISA assay was developed using 62 PCR-confirmed non-hospitalised, mild or moderate COVID-19 samples, ≥14 days post symptom onset and 624 COVID-19 negative samples. The assay was validated using 73 PCR-confirmed non-hospitalised COVID-19 and 359 COVID-19 negative serum samples with an additional 81 DBSs, and further validated in 226 PCR-confirmed non-hospitalised COVID-19 and 426 COVID-19 negative clinical samples.ResultsA sensitivity and specificity of 98.6% (95% CI, 92.6–100.0), 98.3% (95% CI, 96.4–99.4), respectively, was observed following validation of the SARS-CoV-2 ELISA. No cross-reactivities with endemic coronaviruses or other human viruses were observed, and no change in results were recorded for interfering substances. The assay was stable at temperature extremes and components were stable for 15 days once opened. A matrix comparison showed DBS to correlate with serum results. Clinical validation of the assay reported a sensitivity of 94.7% (95% CI, 90.9-97.2%) and a specificity of 98.4% (95% CI, 96.6-99.3%).ConclusionsThe human anti-IgGAM SARS-CoV-2 ELISA provides accurate and sensitive detection of SARS-CoV-2 antibodies in non-hospitalised adults with mild or moderate disease. The use of dried blood spots makes the assay accessible to the wider community.Supplementary MaterialNo

scholarly journals Assessment of Plasmodium antigens and CRP in dried blood spots with multiplex malaria array

2021 ◽  
Author(s):  
Ihn Kyung Jang ◽  
Sara Aranda ◽  
Rebecca Barney ◽  
Andrew Rashid ◽  
Muhammad Helwany ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Whole Blood ◽  
Dried Blood Spots ◽  
Careful Consideration ◽  
Clinical Samples ◽  
Sample Type ◽  
Sample Collection ◽  
Malaria Surveillance ◽  
Inflammatory Biomarker ◽  
Blood Spots

AbstractDried blood spots (DBS) typically prepared on filter papers are an ideal sample type for malaria surveillance by offering easy and cost-effective methods in terms of sample collection, storage, and transport. The objective of this study was to evaluate the applicability of DBS with a commercial multiplex malaria assay, developed to concurrently measure Plasmodium antigens, histidine-rich protein 2 (HRP2), Plasmodium lactate dehydrogenase (pLDH), and a host inflammatory biomarker, C-reactive protein (CRP), in whole blood. The assay conditions were optimized for DBS, and thermal stability for measurement of Plasmodium antigens and CRP in dried blood were determined. Performance of the multiplex assay on matched DBS and whole blood pellet samples was also evaluated using the clinical samples. The results indicate the acceptable performance in multiplex antigen detection using DBS samples. At cutoff levels for DBS, with a diagnostic specificity with a lower 95% confidence bound > 92%, diagnostic sensitivities against polymerase chain reaction (PCR)–confirmed malaria for HRP2, Pf LDH, Pv LDH, and Pan LDH were 93.5%, 80.4%, 21.3%, and 55.6%, respectively. The half-life of pLDH was significantly less than that of HRP2 in thermal stability studies. Results with DBS samples collected from Peru indicate that the uncontrolled storage conditions of DBS can result in inaccurate reporting for infection with P. falciparum parasites with hrp2/3 deletions. With careful consideration that minimizing the unfavorable DBS storage environment is essential for ensuring integrity of heat-labile Plasmodium antigens, DBS samples can be used as an alternative to liquid whole blood to detect P. falciparum with hrp2/3 deletions in malaria surveillance.

A fast high performance liquid chromatographic (HPLC) analysis of amino acid phenylketonuria disorder in dried blood spots and serum samples, employing C18 monolithic silica columns and photo diode array detection

2015 ◽  
Vol 7 (18) ◽  
pp. 7560-7567 ◽  
Author(s):  
Farideh Haghighi ◽  
Zahra Talebpour ◽  
Vali Amini ◽  
Amir Ahmadzadeh ◽  
Mohsen Farhadpour
Keyword(s):  
High Performance ◽  
Hplc Analysis ◽  
Dried Blood Spots ◽  
High Performance Liquid Chromatographic ◽  
Diode Array ◽  
Diode Array Detection ◽  
Serum Samples ◽  
Blood Spots ◽  
Array Detection ◽  
Liquid Chromatographic

A gradient HPLC-PDA method applying a monolithic RP-C18 column for phenylalanine and tyrosine quantization in dried blood spots, within 6 min.

Multiplex Analysis of 230 Medications and 30 Illicit Compounds in Dried Blood Spots and Urine

2020 ◽  
Author(s):  
Christian Tagwerker ◽  
Irfan Baig ◽  
Eric J Brunson ◽  
Davan Dutra-Smith ◽  
Mary-Jane Carias ◽  
...  
Keyword(s):  
Medication Reconciliation ◽  
Dried Blood Spots ◽  
Mass Spectrometry Analysis ◽  
Clinical Samples ◽  
Medication List ◽  
Predictive Values ◽  
Multiplex Analysis ◽  
Blood Spots ◽  
Positive Results ◽  
Urine Specimens

Abstract Drugs of abuse and medication reconciliation testing can benefit from analysis methods capable of detecting a broader range of drug classes and analytes. Mass spectrometry analysis of a wide variety of commonly prescribed medications and over-the-counter drugs per sample also allows for application of a drug–drug interaction (DDI) algorithm to detect adverse drug reactions. In order to prevent adulteration of commonly collected clinical samples such as urine, dried blood spots (DBS) present a reliable alternative. A novel method is described for qualitative and quantitative multiplex analysis of 230 parent drugs, 30 illicit drugs and 43 confirmatory metabolites by HPLC–MS-MS This method is applicable to DBS specimens collected by volumetric absorptive microsamplers and confirmable in urine specimens. A patient cohort (n = 67) providing simultaneous urine specimens and DBS resulted in 100% positive predictive values of medications or illicits confirmed by detection of a parent drug and/or its metabolite during routine medication adherence analysis. An additional 5,508 DBS specimens screened (n = 5,575) showed 5,428 (97%) with an inconsistent positive compared to the provided medication list (including caffeine, cotinine or ethanol metabolites), 29 (0.5%) with no medication list and no unexpected positive results (consistent negative) and 22 (0.4%) showed all positive results matching the provided medication list (consistent positive). A DDI algorithm applied to all positive results revealed 17% with serious and 56% with moderate DDI warnings. Comprehensive DBS analysis proves a reliable alternative to urine drug testing for extended medication reconciliation, with the added advantage of detecting DDIs.

scholarly journals Use of Dried Blood Spots to Elucidate Full-Length Transmitted/Founder HIV-1 Genomes

2016 ◽  
Vol 1 (1) ◽  
pp. 129 ◽  
Author(s):  
Jesus F. Salazar-Gonzalez ◽  
Maria G. Salazar ◽  
Damien C. Tully ◽  
Colin B. Ogilvie ◽  
Gerald H. Learn ◽  
...  
Keyword(s):  
Dried Blood Spots ◽  
Full Length ◽  
Cold Chain ◽  
Clinical Samples ◽  
Envelope Gene ◽  
Acid Extraction ◽  
Resource Limited Settings ◽  
Blood Spots ◽  
Resource Limited ◽  
Hiv 1

Background: Identification of HIV-1 genomes responsible for establishing clinical infection in newly infected individuals is fundamental to prevention and pathogenesis research. Processing, storage, and transportation of the clinical samples required to perform these virologic assays in resource-limited settings requires challenging venipuncture and cold chain logistics. Here, we validate the use of dried-blood spots (DBS) as a simple and convenient alternative to collecting and storing frozen plasma.Methods: We performed parallel nucleic acid extraction, single genome amplification (SGA), next generation sequencing (NGS), and phylogenetic analyses on plasma and DBS.Results: We demonstrated the capacity to extract viral RNA from DBS and perform SGA to infer the complete nucleotide sequence of the transmitted/founder (TF) HIV-1 envelope gene and full-length genome in two acutely infected individuals. Using both SGA and NGS methodologies, we showed that sequences generated from DBS and plasma display comparable phylogenetic patterns in both acute and chronic infection. SGA was successful on samples with a range of plasma viremia, including samples as low as 1,700 copies/ml and an estimated ~50 viral copies per blood spot. Further, we demonstrated reproducible efficiency in gp160 env sequencing in DBS stored at ambient temperature for up to three weeks or at -20ºC for up to five months.Conclusions: These findings support the use of DBS as a practical and cost-effective alternative to frozen plasma for clinical trials and translational research conducted in resource-limited settings.

Incurred sample reanalysis comparison of dried blood spots and plasma samples on the measurement of lopinavir in clinical samples

Bioanalysis ◽  
2012 ◽  
Vol 4 (3) ◽  
pp. 237-240 ◽  
Author(s):  
Roland JW Meesters ◽  
Gero P Hooff ◽  
Rob Gruters ◽  
Jeroen JA van Kampen ◽  
Theo M Luider
Keyword(s):  
Dried Blood Spots ◽  
Clinical Samples ◽  
Plasma Samples ◽  
Blood Spots ◽  
Incurred Sample Reanalysis

scholarly journals Validation and development of an immunonephelometric assay for the determination of alpha-1 antitrypsin levels in dried blood spots from patients with COPD

2013 ◽  
Vol 39 (5) ◽  
pp. 547-554 ◽  
Author(s):  
Laura Russo Zillmer ◽  
Rodrigo Russo ◽  
Beatriz Martins Manzano ◽  
Ivan Ivanaga ◽  
Oliver Augusto Nascimento ◽  
...  
Keyword(s):  
Predictive Value ◽  
Dried Blood Spots ◽  
Serum Samples ◽  
Blood Spots ◽  
Copd Patients ◽  
Resampling Method ◽  
Alpha 1 Antitrypsin ◽  
Sensitivity Specificity ◽  
Immunonephelometric Assay

OBJECTIVE: To validate and develop an immunonephelometric assay for the determination of alpha-1 antitrypsin (AAT) levels in dried blood spots from COPD patients in Brazil. METHODS: We determined AAT levels in serum samples and dried blood spots from 192 COPD patients. For the preparation of dried blood spots, a disk (diameter, 6 mm) was placed into a tube, eluted with 200 µL of PBS, and stored overnight at 4ºC. All of the samples were analyzed by immunonephelometry in duplicate. We used the bootstrap resampling method in order to determine a cut-off point for AAT levels in dried blood spots. RESULTS: The correlation coefficient between the AAT levels in serum samples and those in dried blood spots was r = 0.45. For dried blood spots, the cut-off value was 2.02 mg/dL (97% CI: 1.45-2.64 mg/dL), with a sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 95.7%, 27.2%, and 100%, respectively. CONCLUSIONS: This method for the determination of AAT levels in dried blood spots appears to be a reliable screening tool for patients with AAT deficiency.

Simplified 25-Hydroxyvitamin D Standardization and Optimization in Dried Blood Spots by LC-MS/MS

2017 ◽  
Vol 100 (5) ◽  
pp. 1328-1336 ◽  
Author(s):  
Andrew J Makowski ◽  
John A Rathmacher ◽  
Ronald L Horst ◽  
Christopher T Sempos
Keyword(s):  
Vitamin D ◽  
Dried Blood Spots ◽  
Serum Concentrations ◽  
Vitamin D Binding Protein ◽  
Serum Samples ◽  
Blood Spots ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Sample Representation ◽  
Concentration Assessment

Abstract Previous studies have assessed vitamin D status based on the 25-hydroxyvitamin D [25(OH)D] concentration measured in samples from dried blood spots (DBSs). In 40 individuals participating in a clinical study, we compared 25(OH)D levels measured from DBSs and in serum using an LC-MS/MS reference procedure in collaboration with the Vitamin D Standardization Program. The main objective was to simplify and optimize current methods to produce an assay that can be used as a screening tool for 25(OH)D concentration assessment without derivatization. The DBS 25(OH)D levels, compared to serum concentrations, were found to have 101% accuracy overall, and the correlation coefficient (r) was 0.83 (P < 0.0001), with a significant linear relationship. Free 25(OH)D and vitamin D binding protein (VDBP) were assessed in the serum samples for potential correlations to the DBS calculations: the levels of free 25(OH)D had moderate to strong correlation to DBS and serum concentrations, with r values of 0.67 (P < 0.0001) and 0.76 (P < 0.0001), respectively. VDBP and hematocrit had no significant correlation to either DBS or serum sample types, with r values <0.1. In conclusion, the useof two DBSs and an increase in DBS sample size improved overall sample representation without the need for derivatization, and produced an accurate and robust method that can be used to screen 25(OH)D levels.

scholarly journals Application of Dried Blood Spots and Serum Samples for the Determination of Vitamin D Metabolites in the Group of Healthy Women and with Hashimoto’s Thyroiditis

2021 ◽  
Author(s):  
R. Rola ◽  
E. Trusewicz ◽  
T. Bieńkowski ◽  
S. Studzińska
Keyword(s):  
Vitamin D ◽  
Hashimoto’S Thyroiditis ◽  
Good Alternative ◽  
Dried Blood Spots ◽  
Hashimoto's Thyroiditis ◽  
Vitamin D Metabolites ◽  
Serum Samples ◽  
Blood Spots ◽  
Healthy Women

Abstract Purpose The relationship between Hashimoto's thyroiditis and vitamin D concentration was already presented in many studies. The aim of this study was to analyze the differences in the concentration of vitamin D metabolites between healthy women and women with Hashimoto's thyroiditis (HT). Methods The quantitative analysis of five vitamin D metabolites was carried out using liquid chromatography coupled with tandem mass spectrometry. The analyzed materials were serum and dried blood spots (DBS). The results obtained for the two materials were also compared. Results No statistically significant differences were found in the mean concentration of the 25(OH)D3, 25(OH)D2, 24,25(OH)2D3, 1,25(OH)2D3 metabolites between the test and the control groups. However, a strong correlation was found between the 25(OH)D3 and 24,25(OH)2D3 metabolites. Conclusion The study showed that healthy women and women with Hashimoto's disease had similar concentration of vitamin D metabolites. Research also proved that DBS is a good alternative to serum. The differences in 25(OH)D concentration were not statistically significant (17.0 and 15.5 ng mL−1 for serum and DBS, respectively). DBS can be successfully used in research on a large group of people, since the process of material collection, as well as sample preparation, is fast and simple. It is also easy to transport and store, and requires small volume of blood.

scholarly journals Antibody signatures of asymptomatic Plasmodium falciparum malaria infections measured from dried blood spots

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Christine F. Markwalter ◽  
Myat Htut Nyunt ◽  
Zay Yar Han ◽  
Ricardo Henao ◽  
Aarti Jain ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Specific Antibody ◽  
Predictive Value ◽  
Dried Blood Spots ◽  
Protein Microarrays ◽  
Antibody Responses ◽  
Antibody Activity ◽  
Low Density ◽  
Blood Spots ◽  
Diagnostic Characteristics

Abstract Background Screening malaria-specific antibody responses on protein microarrays can help identify immune factors that mediate protection against malaria infection, disease, and transmission, as well as markers of past exposure to both malaria parasites and mosquito vectors. Most malaria protein microarray work has used serum as the sample matrix, requiring prompt laboratory processing and a continuous cold chain, thus limiting applications in remote locations. Dried blood spots (DBS) pose minimal biohazard, do not require immediate laboratory processing, and are stable at room temperature for transport, making them potentially superior alternatives to serum. The goals of this study were to assess the viability of DBS as a source for antibody profiling and to use DBS to identify serological signatures of low-density Plasmodium falciparum infections in malaria-endemic regions of Myanmar. Methods Matched DBS and serum samples from a cross-sectional study in Ingapu Township, Myanmar were probed on protein microarrays populated with P. falciparum antigen fragments. Signal and trends in both sample matrices were compared. A case-control study was then performed using banked DBS samples from malaria-endemic regions of Myanmar, and a regularized logistic regression model was used to identify antibody signatures of ultrasensitive PCR-positive P. falciparum infections. Results Approximately 30% of serum IgG activity was recovered from DBS. Despite this loss of antibody activity, antigen and population trends were well-matched between the two sample matrices. Responses to 18 protein fragments were associated with the odds of asymptomatic P. falciparum infection, albeit with modest diagnostic characteristics (sensitivity 58%, specificity 85%, negative predictive value 88%, and positive predictive value 52%). Conclusions Malaria-specific antibody responses can be reliably detected, quantified, and analysed from DBS, opening the door to serological studies in populations where serum collection, transport, and storage would otherwise be impossible. While test characteristics of antibody signatures were insufficient for individual diagnosis, serological testing may be useful for identifying exposure to asymptomatic, low-density malaria infections, particularly if sero-surveillance strategies target individuals with low previous exposure as sentinels for population exposure.

scholarly journals Dynamics of neutralizing antibody responses in acute-phase COVID-19: A potential relationship between disease progression and rapid neutralizing antibody response

2021 ◽  
Author(s):  
Hitoshi Kawasuji ◽  
Yoshitomo Morinaga ◽  
Hideki Tani ◽  
Miyuki Kimura ◽  
Hiroshi Yamada ◽  
...  
Keyword(s):  
Neutralization Test ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Pseudotyped Virus ◽  
Serum Samples ◽  
Neutralization Activity ◽  
Neutralizing Activity ◽  
Time Points ◽  
Moderate Disease ◽  
Activity Dynamics

AbstractIntroductionAdaptive immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dynamics remain largely unknown. The neutralizing antibody (NAb) levels in patients with coronavirus disease 2019 (COVID-19) are helpful for understanding the pathology.Patients and MethodsUsing SARS-CoV-2 pseudotyped virus, serum sample neutralization values in symptomatic COVID-19 patients were measured using the chemiluminescence reduction neutralization test (CRNT). At least two sequential serum samples collected during hospitalization were analyzed to assess NAbs neutralizing activity dynamics at different time points.ResultsOf the 11 patients, four (36.4%), six (54.5%), and one (9.1%) had moderate, severe, and critical disease, respectively. Fifty percent neutralization (N50%-CRNT) was observed upon admission in 90.9% (10/11); all patients acquired neutralizing activity 2–12 days after onset. In patients with moderate disease, neutralization was observed at earliest within two days after symptom onset. In patients with severe-to-critical disease, neutralization activity increased, plateauing 9–16 days after onset. Neutralization activity on admission was significantly higher in patients with moderate disease than in patients with severe-to-critical disease (relative % of infectivity, 6.4% vs. 41.1%; P=.0011).ConclusionsNeutralization activity on admission inversely correlated with disease severity. The rapid NAb response may play a crucial role in preventing the progression of COVID-19.

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