scholarly journals Precision of Serologic Testing from Dried Blood Spots Using a Multiplex Bead Assay

2021 ◽  
Author(s):  
Sarah Gwyn ◽  
Solomon Aragie ◽  
Dionna M. Wittberg ◽  
Jason S. Melo ◽  
Adane Dagnew ◽  
...  
Keyword(s):  
Test Performance ◽  
Salmonella Enteritidis ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Dried Blood Spots ◽  
Antibody Responses ◽  
Kappa Statistics ◽  
Blood Spots ◽  
Serologic Testing ◽  
Multiplex Bead

Multiplex bead assays (MBAs) for serologic testing have become more prevalent in public health surveys, but few studies have assessed their test performance. As part of a trachoma study conducted in a rural part of Ethiopia in 2016, dried blood spots (DBS) were collected from a random sample of 393 children aged 0 to 9 years, with at least two separate 6-mm DBS collected on a filter card. Samples eluted from DBS were processed using an MBA on the Luminex platform for antibodies against 13 antigens of nine infectious organisms: Chlamydia trachomatis, Vibrio cholera, enterotoxigenic Escherichia coli, Cryptosporidium parvum, Entamoeba histolytica, Camplyobacter jejuni, Salmonella typhimurium Group B, Salmonella enteritidis Group D, and Giardia lamblia. Two separate DBS from each child were processed. The first DBS was run a single time, with the MBA set to read 100 beads per well. The second DBS was run twice, first at 100 beads per well and then at 50 beads per well. Results were expressed as the median fluorescence intensity minus background (MFI–BG), and classified as seropositive or seronegative according to external standards. Agreement between the three runs was high, with intraclass correlation coefficients of > 0.85 for the two Salmonella antibody responses and > 0.95 for the other 11 antibody responses. Agreement was also high for the dichotomous seropositivity indicators, with Cohen’s kappa statistics exceeding 0.87 for each antibody assay. These results suggest that serologic testing on the Luminex platform had strong test performance characteristics for analyzing antibodies using DBS.

scholarly journals Measurement of Glycated Hemoglobin A1c from Dried Blood by Turbidimetric Immunoassay

2009 ◽  
Vol 3 (5) ◽  
pp. 1203-1206 ◽  
Author(s):  
Ramakrishnan Lakshmy ◽  
Ruby Gupta
Keyword(s):  
Whole Blood ◽  
Large Scale ◽  
Hemoglobin A1c ◽  
Glycated Hemoglobin ◽  
Intraclass Correlation ◽  
Dried Blood Spots ◽  
Sample Collection ◽  
Blood Spots ◽  
Glycated Hemoglobin A1c ◽  
The Impact

Background: Glycated hemoglobin A1c (A1C) is an important marker in the diagnosis and treatment of diabetes. Dried blood measurement of A1C is useful in large scale epidemiological evaluation of A1C, especially to assess the impact of intervention programs. The possibility of using dried blood for measurement of A1C by the immunoturbidimetric method was explored in the present study. Method: Blood was collected from 30 patients, and blood spots were prepared and dried. The dried blood spot samples were kept for different lengths of time at 4°C to assess stability. Glycated hemoglobin was measured in whole blood and dried blood on the day of collection as well as on days 10 and 15 by immunoturbidimetric method. Results: The A1C values of 30 samples analyzed for comparison between whole blood estimation and dried blood ranged from 4.6% to 9.9%. The mean A1C on the day of sample collection was 6.01% ± 1.58% in fresh whole blood samples and 5.94% ± 1.58 % in dried blood spots. A linear and highly correlated relationship was observed between dried blood A1C values and those in whole blood ( r = 0.986 and intraclass correlation value = 0.993). Glycated hemoglobin values on day 10 and day 15 were comparable with the values on day 1 with a shift in mean of just 1% on day 10 and 3.04% on day 15. Conclusion: In conclusion, dried blood can be used for measurement of A1C by immunoturbidimetric method, and further stability of A1C measurement from dried blood for up to 15 days at 4°C makes it an ideal matrix for transportation in developing countries like India.

scholarly journals A novel, reproducible, and objective method for volumetric magnetic resonance imaging assessment of enhancing glioblastoma

2014 ◽  
Vol 121 (3) ◽  
pp. 536-542 ◽  
Author(s):  
Charles W. Kanaly ◽  
Ankit I. Mehta ◽  
Dale Ding ◽  
Jenny K. Hoang ◽  
Peter G. Kranz ◽  
...  
Keyword(s):  
Interobserver Variability ◽  
Intraclass Correlation ◽  
Evaluation Criteria ◽  
Correlation Coefficients ◽  
Response Assessment ◽  
Volumetric Method ◽  
Kappa Statistics ◽  
Macdonald Criteria ◽  
Automated Method ◽  
Radiological Response

Object Robust methodology that allows objective, automated, and observer-independent measurements of brain tumor volume, especially after resection, is lacking. Thus, determination of tumor response and progression in neurooncology is unreliable. The objective of this study was to determine if a semi-automated volumetric method for quantifying enhancing tissue would perform with high reproducibility and low interobserver variability. Methods Fifty-seven MR images from 13 patients with glioblastoma were assessed using our method, by 2 neuroradiologists, 1 neurosurgeon, 1 neurosurgical resident, 1 nurse practitioner, and 1 medical student. The 2 neuroradiologists also performed traditional 1-dimensional (1D) and 2-dimensional (2D) measurements. Intraclass correlation coefficients (ICCs) assessed interobserver variability between measurements. Radiological response was determined using Response Evaluation Criteria In Solid Tumors (RECIST) guidelines and Macdonald criteria. Kappa statistics described interobserver variability of volumetric radiological response determinations. Results There was strong agreement for 1D (RECIST) and 2D (Macdonald) measurements between neuroradiologists (ICC = 0.42 and 0.61, respectively), but the agreement using the authors' novel automated approach was significantly stronger (ICC = 0.97). The volumetric method had the strongest agreement with regard to radiological response (κ = 0.96) when compared with 2D (κ = 0.54) or 1D (κ = 0.46) methods. Despite diverse levels of experience of the users of the volumetric method, measurements using the volumetric program remained remarkably consistent in all users (0.94). Conclusions Interobserver variability using this new semi-automated method is less than the variability with traditional methods of tumor measurement. This new method is objective, quick, and highly reproducible among operators with varying levels of expertise. This approach should be further evaluated as a potential standard for response assessment based on contrast enhancement in brain tumors.

scholarly journals The interobserver reliability of the diagnosis and classification of scaphoid fractures using high-resolution peripheral quantitative CT

2020 ◽  
Vol 102-B (4) ◽  
pp. 478-484 ◽  
Author(s):  
Anne M. Daniels ◽  
Caroline E. Wyers ◽  
Heinrich M. J. Janzing ◽  
Sander Sassen ◽  
Daan Loeffen ◽  
...  
Keyword(s):  
High Resolution ◽  
Interobserver Agreement ◽  
Interobserver Reliability ◽  
Scaphoid Fracture ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Kappa Statistics ◽  
Quantitative Ct ◽  
Scaphoid Fractures

Aims Besides conventional radiographs, the use of MRI, CT, and bone scintigraphy is frequent in the diagnosis of a fracture of the scaphoid. However, which techniques give the best results remain unknown. The investigation of a new imaging technique initially requires an analysis of its precision. The primary aim of this study was to investigate the interobserver agreement of high-resolution peripheral quantitative CT (HR-pQCT) in the diagnosis of a scaphoid fracture. A secondary aim was to investigate the interobserver agreement for the presence of other fractures and for the classification of scaphoid fracture. Methods Two radiologists and two orthopaedic trauma surgeons evaluated HR-pQCT scans of 31 patients with a clinically-suspected scaphoid fracture. The observers were asked to determine the presence of a scaphoid or other fracture and to classify the scaphoid fracture based on the Herbert classification system. Fleiss kappa statistics were used to calculate the interobserver agreement for the diagnosis of a fracture. Intraclass correlation coefficients (ICCs) were used to assess the agreement for the classification of scaphoid fracture. Results A total of nine (29%) scaphoid fractures and 12 (39%) other fractures were diagnosed in 20 patients (65%) using HR-pQCT across the four observers. The interobserver agreement was 91% for the identification of a scaphoid fracture (95% confidence interval (CI) 0.76 to 1.00) and 80% for other fractures (95% CI 0.72 to 0.87). The mean ICC for the classification of a scaphoid fracture in the seven patients diagnosed with scaphoid fracture by all four observers was 73% (95% CI 0.42 to 0.94). Conclusion We conclude that the diagnosis of scaphoid and other fractures is reliable when using HR-pQCT in patients with a clinically-suspected fracture. Cite this article: Bone Joint J 2020;102-B(4):478–484.

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 Performance of PURE-LAMP to Detect Declining Prevalence of Malaria in Haiti

2020 ◽  
Author(s):  
Jeanne Perpétue VINCENT ◽  
Alexandre Valcena Existe ◽  
Kanako Komaki-Yasuda ◽  
Jacques Boncy ◽  
Shigeyuki Kano
Keyword(s):  
Nested Pcr ◽  
Diagnostic Method ◽  
Dried Blood Spots ◽  
World Health ◽  
Lamp Method ◽  
Kappa Statistics ◽  
Predictive Values ◽  
Blood Spots ◽  
The World ◽  
Asymptomatic Subjects

Abstract Background Malaria continues to cause burden in various parts of the world. Endemic countries are developing schemes to end this nuisance in accordance with the World Health Organization’s Global Technical Strategy for Malaria 2016–2030. Haiti, a Caribbean country, is among those aiming to eliminate malaria within a few years. Two surveys were conducted in Haiti in the summers of 2017 and 2018, respectively, during which we aimed to evaluate the performance of the simple and rapid PURE-LAMP (procedure for ultra-rapid extraction–loop-mediated isothermal amplification) method with dried blood spots as an alternative diagnostic method for malaria in the context of low to very low rates of transmission.Methods Febrile and asymptomatic subjects were recruited from three administrative divisions within Haiti. Their blood samples were tested by microscopy, rapid diagnostic tests (RDT), PURE-LAMP and nested PCR to detect Plasmodium infection. The positive rates for the two study periods as determined by the different methods were compared. Sensitivity, specificity, positive and negative predictive values and kappa statistics were estimated with the nested PCR results as the gold standard.Results Among 1074 samples analyzed, a positive rate of 8.3% was calculated based on the nested PCR results. Among symptomatic subjects, the rates in 2017 and 2018 were 14.6% and 1.4%, respectively. Three positives were detected among 172 asymptomatic participants in 2018 by PURE-LAMP and nested PCR, and all three were from the same locality. No asymptomatic subjects were recruited in 2017. The PURE-LAMP, RDT and microscopy had respective sensitivities of 100%, 85.4% and 49.4%. All of the testing methods had specificities over 99%.Conclusion The prevalence of malaria was found to have substantially decreased in 2018 in Haiti. A specific focus of infection appeared to require intervention with a sensitive malaria diagnostic method and treatment. This study confirmed the high performance of the PURE-LAMP method with dried blood spots and recommends its use in targeted mass screening and treatment activities in low endemic areas of malaria.

Validity and Reliability of the Comfort Behavior Scale in Children Undergoing Wound Dressing Replacement in Vietnam

MedPharmRes ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 24-31
Author(s):  
Huong Lan Thi Tran ◽  
Katrina Einhellig ◽  
Linh Thuy Khanh Tran ◽  
Oanh Hoang Thi Pham ◽  
Cuc Thu Thi Tran ◽  
...  
Keyword(s):  
Wound Dressing ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
World Health ◽  
Kappa Statistics ◽  
Validity And Reliability ◽  
Rater Reliability ◽  
Behavior Scale ◽  
Health Organization ◽  
Children's Pain

Background: This study translated and culturally adapted the Comfort Behavior Scale (Comfort-B) into Vietnamese using a standard protocol guided by the World Health Organization. Methods: The Comfort-B was translated into Vietnamese and then English back-translated by independent translators. These versions were reviewed and assessed by a Vietnamese expert’s panel and an English expert’s panel. Thirty-four nurses of the Nhi Dong 1 Hospital were invited to use the Vietnamese Comfort-B to assess pain while watching five videos recorded before, during and after wound dressing replacement. The eight characteristics of the Vietnamese Comfort-B were assessed by 34 nurses. Fifteen nurses agreed to do the second assessment two weeks from the first assessment. The content validity index was used to assess the relevance and clarity of all items and the whole scale. Agreements between raters were explored using Kappa statistics. Intraclass correlation coefficients (ICC) were used to assess intra-rater and inter-rater reliability. Multi-level linear regression was used to assess changes in the Vietnamese Comfort-B before, during and after wound dressing replacement between two assessments. Results: The Vietnamese Comfort-B was accredited by the Vietnamese expert’s panel. The English-back translated version was approved by the English expert’s panel. The nurses agreed that the Vietnamese Comfort-B can be used in clinical practice and research. Kappas of all items were ≥0.96 indicating excellent agreement between raters. Alpha coefficients of two assessments were ≥0.97 indicating excellent internal consistency. All ICCs ≥ 0.79 indicated good intra-rater and inter-rater reliability. Conclusions: The study suggested that the Vietnamese Comfort-B can be used for future studies assessing children’s pain in the local hospital context.

A Quantitative Food Frequency Questionnaire for Women in Southeast China: Development and Reproducibility

2005 ◽  
Vol 17 (1) ◽  
pp. 29-35 ◽  
Author(s):  
M. Zhang ◽  
CW Binns ◽  
AH Lee
Keyword(s):  
Food Frequency Questionnaire ◽  
Eating Habits ◽  
Chinese Women ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Food Group ◽  
Kappa Statistics ◽  
Food Frequency ◽  
Southeast China ◽  
Intraclass Correlation Coefficients

This study describes the development and reproducibility of a 128-item quantitative food frequency questionnaire (FFQ) to measure usual food consumption for women in southeast China. The FFQ was pre-tested using 51 Chinese women who recently migrated to Australia. Cronbach's alpha coefficient was 0.81 for internal consistency. The reliability of the FFQ was then assessed by another test-retest study. A sample of 41 women residing in southeast China was interviewed twice within 12 weeks. Intraclass correlation coefficients were moderate to high for mean food group consumption (0.43-0.96) and mean daily nutrient intakes (0.47-0.89). Kappa statistics for eating habits ranged from 0.27 to 0.89 in the test-retest. The mean ratio of energy intake to basal metabolic rate was 1.73 (S.D. 0.39) in both test and retest samples. The study confirmed that the FFQ method using standard containers is appropriate to assess dietary intake for women in southeast China. Asia Pac J Public Health 2005: 17(1): 29-35.

scholarly journals Reliability and clinical applicability of a novel tear film imaging tool

2021 ◽  
Author(s):  
Noémi Tóth ◽  
Eszter Szalai ◽  
Tibor Rák ◽  
Veronika Lillik ◽  
Attila Nagy ◽  
...  
Keyword(s):  
Intraclass Correlation ◽  
Tear Film ◽  
Correlation Coefficients ◽  
Kappa Statistics ◽  
Ophthalmological Examination ◽  
Non Invasive ◽  
Imaging Tool ◽  
Clinical Applicability ◽  
Break Up

Abstract Purpose The aim of our research was to investigate the reliability and clinical applicability of a modern tear film imaging tool by comparing the inter- and intragrader difference. The further goal was to compare the non-invasive tear break-up time (NIBUT) measured with the LacryDiag® device with traditional tear film break-up time (TBUT). Methods Comprehensive ophthalmological examination was performed, including LacryDiag® (Quantel Medical, France) (lower tear meniscus height measuring (LTMH), superior and inferior eyelid meibography (MeibS MeibI), interferometry (INT), NIBUT), slit lamp examination, and TBUT. Two independent, well-trained graders selected and analyzed the LTMH, MeibI, MeibS, and INT. The second grader reanalyzed the data 1 month later. Intra- and inter-examiner reliabilities were evaluated using intraclass correlation coefficients (ICC), while for categorical variable, Cohen’s kappa statistics were provided. The Bland-Altman plot was used for visualization of the agreement between measurements. Results Fifty healthy volunteers were examined. For LTMH both the inter- and intragrader variabilities were excellent. Between two graders, the ICC of MeibI was poor; however, between two graders, the ICC of MeibS was good, and the intragrader variability in MeibI and MeibS was excellent. For the INT, both intra- and intergrading were in fair and moderate agreement, although the intragrader agreement was higher. Comparing the NIBUT and TBUT, the agreement was slight. Conclusion Based on our results, examination of a patient during follow-up should be performed by the same examiner, because of the slight agreement. The LacryDiag® is a non-invasive, easy-to-use device, which can examine the tear film and save the recordings for easier follow-up.

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.

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