scholarly journals A rapid point-of-care assay accurately measures vitamin D

2021 ◽  
Author(s):  
K. Albrecht ◽  
J. Lotz ◽  
L. Frommer ◽  
K. J. Lackner ◽  
G. J. Kahaly
Keyword(s):  
Vitamin D ◽  
Metabolic Pathways ◽  
Point Of Care ◽  
Immunofluorescence Assay ◽  
Laboratory Method ◽  
Controlled Study ◽  
Mean Deviation ◽  
Serum Samples ◽  
Assay Validation ◽  
Accuracy And Precision

Abstract Purpose Vitamin D (VitD) is a pleiotropic hormone with effects on a multitude of systems and metabolic pathways. Consequently, the relevance of a sufficiently high VitD serum level becomes self-evident. Methods A rapid immunofluorescence assay designed for the point-of-care measurement of serum VitD3 solely was tested. Inter- and intra-assay validation, double testing and result comparison with a standardized laboratory method were performed. Results An overall linear correlation of r = 0.89 (Pearson, 95% CI 0.88–0.92, p < 0.01) between the point of care and the conventional reference assay was registered. Accuracy and precision were of special interest at cut-points (10 ng/ml [mean deviation 1.7 ng/ml, SD 1.98 ng/ml, SE 0.16 ng/ml], 12 ng/ml [MD 0.41, SD 1.89, SE 0.19] and 30 ng/ml [MD − 1.11, SD 3.89, SE 0.35]). Only a slight deviation was detected between the two assays when using fresh (r = 0.91, 95% CI 0.86–0.94, p < 0.01) and frozen serum samples (r = 0.86, 0.82–0.89, p < 0.01). Results remained steady when samples were frozen several times. Inter- and intra-assay validation according to the CLSI protocol as well as multiuser testing showed stable results. Conclusion This novel, innovative, and controlled study indicates that the evaluated rapid point of care VitD assay is reliable, accurate, and suited for clinical practice.

scholarly journals Point-of-care high-sensitivity assay on PATHFAST as the backup in the emergency room

2021 ◽  
Vol 5 ◽  
pp. 239920262110550
Author(s):  
Joško Osredkar ◽  
Katja Krivic ◽  
Teja Fabjan ◽  
Kristina Kumer ◽  
Jure Tršan ◽  
...  
Keyword(s):  
Blood Serum ◽  
Troponin I ◽  
Point Of Care ◽  
High Sensitivity ◽  
Turnaround Time ◽  
Serum Samples ◽  
Linear Relationships ◽  
Accuracy And Precision ◽  
Laboratory Results ◽  
Key Indicators

Aim: Although the levels of cardiac troponin I (cTnI) have proved to be a useful diagnostic biomarker of acute myocardial infarction, there are a wide variety of point-of-care (POC) analysers, which provide measurements of cTnI. The aim of this study was to compare the results obtained by the ADVIA Centaur ultra-assay cTnI assay (us-cTnI), ADVIA Centaur high-sensitive cTnI assay (hs-cTnI) and a POC high-sensitivity assay using PATHFAST. We also aimed to explore total turnaround time (TAT) for laboratory results using the POC PATHFAST analyser. Methods: Samples from 161 patients were taken. Of these samples, 129 were tested with all three assays (us-cTnI, hs-cTnI and PATHFAST), and 32 samples were tested on PATHFAST for the comparison of whole blood, serum and plasma. Results: Comparison of the POC testing methods in this study demonstrated that there are strong linear relationships between all three cTnI assays (us-cTnI, hs-cTnI and POC on PATHFAST). Furthermore, we also show there are strong linear relationships between the two high-sensitive cTnI assays (hs-cTnI and PATHFAST) for blood serum samples, as determined by Passing–Bablok regression analyses. In our comparison of our new data with our older study, the TAT went down. Conclusion: The timeliness of laboratory results is, in addition to accuracy and precision, one of the key indicators of laboratory performance, and at the same time has a significant impact on the course of the patient’s condition. It is therefore important that the laboratory strives to meet the expectations of clinicians regarding the time from the order to the result of the analysis.

scholarly journals Determinants and Measurement of Neonatal Vitamin D: Overestimation of 25(OH)D in Cord Blood Using CLIA Assay Technology

2019 ◽  
Vol 105 (4) ◽  
pp. e1085-e1092
Author(s):  
Mengdi Lu ◽  
Bruce W Hollis ◽  
Vincent J Carey ◽  
Nancy Laranjo ◽  
Ravinder J Singh ◽  
...  
Keyword(s):  
Vitamin D ◽  
Cord Blood ◽  
Late Pregnancy ◽  
First Trimester ◽  
Controlled Study ◽  
Positive Bias ◽  
Third Trimester ◽  
Serum Samples ◽  
Human Cord Blood ◽  
Blood Samples

Abstract Context Vitamin D (VD) deficiency in pregnancy and the neonatal period has impacts on childhood outcomes. Maternal VD sufficiency is crucial for sufficiency in the neonate, though the effect of early versus late pregnancy 25-hydroxy-vitamin D (25(OH)D) levels on neonatal levels is unknown. Furthermore, chemiluminescence immunoassays (CLIAs) are widely used, though their validity in measuring 25(OH)D specifically in cord blood specimens has not been established. Objective To assess the validity of a CLIA in the measurement of cord blood 25(OH)D and to evaluate maternal determinants of neonatal 25(OH)D, including early versus late pregnancy 25(OH)D levels. Design This is an ancillary analysis from the Vitamin D Antenatal Asthma Reduction Trial (VDAART), a randomized, double-blinded, placebo-controlled study. Participants and Intervention A total of 881 pregnant women at high risk of having offspring asthma were randomized to receive VD supplementation or placebo. Serum samples were collected from mothers in early and late pregnancy and from offspring cord blood at birth. 25(OH)D levels were assayed by CLIA in all maternal and offspring samples and by LC-MS/MS in all offspring samples and a subset of 200 maternal third trimester samples. Results Cord blood 25(OH)D levels were higher as measured by CLIA (mean 37.13 ng/mL [SD 18.30]) than by LC-MS/MS (mean 23.54 ng/mL [SD 11.99]), with a mean positive bias of 13.54 ng/mL (SD 12.92) by Bland-Altman analysis. This positive bias in measurement by CLIA was not observed in maternal samples. Third trimester 25(OH)D was a positive determinant of neonatal 25(OH)D levels. Conclusion Chemiluminescence immunoassays overestimate 25(OH)D levels in human cord blood samples, an effect not observed in maternal blood samples. The quantification of 25(OH)D by CLIA should therefore not be considered valid when assayed in cord blood samples. Third trimester, but not first trimester, maternal 25(OH)D is one of several determinants of neonatal 25(OH)D status.

Ferromagnetic Resonance Biosensor for Homogeneous and Volumetric Detection of DNA

2017 ◽  
Author(s):  
Bo Tian ◽  
Peter Svedlindh ◽  
Mattias Strömberg ◽  
Erik Wetterskog
Keyword(s):  
Magnetic Nanoparticles ◽  
Ferromagnetic Resonance ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rolling Circle Amplification ◽  
Resonance Field ◽  
Isothermal Amplification ◽  
Detection Sensitivity ◽  
Serum Samples ◽  
Rolling Circle

In this work, we demonstrate for the first time, a ferromagnetic resonance (FMR) based homogeneous and volumetric biosensor for magnetic label detection. Two different isothermal amplification methods, <i>i.e.</i>, rolling circle amplification (RCA) and loop-mediated isothermal amplification (LAMP) are adopted and combined with a standard electron paramagnetic resonance (EPR) spectrometer for FMR biosensing. For RCA-based FMR biosensor, binding of RCA products of a synthetic Vibrio cholerae target DNA sequence gives rise to the formation of aggregates of magnetic nanoparticles. Immobilization of nanoparticles within the aggregates leads to a decrease of the net anisotropy of the system and a concomitant increase of the resonance field. A limit of detection of 1 pM is obtained with an average coefficient of variation of 0.16%, which is superior to the performance of other reported RCA-based magnetic biosensors. For LAMP-based sensing, a synthetic Zika virus target oligonucleotide is amplified and detected in 20% serum samples. Immobilization of magnetic nanoparticles is induced by their co-precipitation with Mg<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (a by-product of LAMP) and provides a detection sensitivity of 100 aM. The fast measurement, high sensitivity and miniaturization potential of the proposed FMR biosensing technology makes it a promising candidate for designing future point-of-care devices.<br>

scholarly journals A Label and Probe-Free Zika Virus Immunosensor Prussian Blue@carbon Nanotube-Based for Amperometric Detection of the NS2B Protein

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 157
Author(s):  
Bárbara V. M. Silva ◽  
Marli T. Cordeiro ◽  
Marco A. B. Rodrigues ◽  
Ernesto T. A. Marques ◽  
Rosa F. Dutra
Keyword(s):  
Carbon Nanotube ◽  
Prussian Blue ◽  
Zika Virus ◽  
Point Of Care ◽  
Amperometric Detection ◽  
Cross Reactivity ◽  
Structural Protein ◽  
Serum Samples ◽  
Polypyrrole Composite ◽  
Congenital Disabilities

Zika virus (ZIKV) is a mosquito-borne infection, predominant in tropical and subtropical regions causing international concern due to the ZIKV disease having been associated with congenital disabilities, especially microcephaly and other congenital abnormalities in the fetus and newborns. Development of strategies that minimize the devastating impact by monitoring and preventing ZIKV transmission through sexual intercourse, especially in pregnant women, since no vaccine is yet available for the prevention or treatment, is critically important. ZIKV infection is generally asymptomatic and cross-reactivity with dengue virus (DENV) is a global concern. An innovative screen-printed electrode (SPE) was developed for amperometric detection of the non-structural protein (NS2B) of ZIKV by exploring the intrinsic redox catalytic activity of Prussian blue (PB), incorporated into a carbon nanotube–polypyrrole composite. Thus, this immunosensor has the advantage of electrochemical detection without adding any redox-probe solution (probe-less detection), allowing a point-of-care diagnosis. It was responsive to serum samples of only ZIKV positive patients and non-responsive to negative ZIKV patients, even if the sample was DENV positive, indicating a possible differential diagnosis between them by NS2B. All samples used here were confirmed by CDC protocols, and immunosensor responses were also checked in the supernatant of C6/36 and in Vero cell cultures infected with ZIKV.

scholarly journals Vitamin D Metabolites and Clinical Outcome in Hospitalized COVID-19 Patients

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2129
Author(s):  
Sieglinde Zelzer ◽  
Florian Prüller ◽  
Pero Curcic ◽  
Zdenka Sloup ◽  
Magdalena Holter ◽  
...  
Keyword(s):  
Vitamin D ◽  
Degradation Products ◽  
University Hospital ◽  
Vitamin D Metabolites ◽  
Serum Concentrations ◽  
Serum Samples ◽  
Liquid Chromatography Tandem Mass ◽  
Relevant Role ◽  
Metabolite Ratio ◽  
The University

(1) Background: Vitamin D, a well-established regulator of calcium and phosphate metabolism, also has immune-modulatory functions. An uncontrolled immune response and cytokine storm are tightly linked to fatal courses of COVID-19. The present retrospective study aimed to inves-tigate vitamin D status markers and vitamin D degradation products in a mixed cohort of 148 hospitalized COVID-19 patients with various clinical courses of COVID-19. (2) Methods: The serum concentrations of 25(OH)D3, 25(OH)D2, 24,25(OH)2D3, and 25,26(OH)2D3 were determined by a validated liquid-chromatography tandem mass-spectrometry method in leftover serum samples from 148 COVID-19 patients that were admitted to the University Hospital of the Medical Uni-versity of Graz between April and November 2020. Anthropometric and clinical data, as well as outcomes were obtained from the laboratory and hospital information systems. (3) Results: From the 148 patients, 34 (23%) died within 30 days after admission. The frequency of fatal outcomes did not differ between males and females. Non-survivors were significantly older than survivors, had higher peak concentrations of IL-6 and CRP, and required mechanical ventilation more frequently. The serum concentrations of all vitamin D metabolites and the vitamin D metabolite ratio (VMR) did not differ significantly between survivors and non-survivors. Additionally, the need for res-piratory support was unrelated to the serum concentrations of 25(OH)D vitamin D and the two vitamin D catabolites, as well as the VMR. (4) Conclusion: The present results do not support a relevant role of vitamin D for the course and outcome of COVID-19.

Reactivity of serum samples from patients with a flavivirus infection measured by immunofluorescence assay and ELISA

2002 ◽  
Vol 4 (12) ◽  
pp. 1209-1215 ◽  
Author(s):  
Penelopie Koraka ◽  
Herve Zeller ◽  
Matthias Niedrig ◽  
Albert D.M.E Osterhaus ◽  
Jan Groen
Keyword(s):  
Immunofluorescence Assay ◽  
Serum Samples ◽  
Flavivirus Infection

Optimization of Automated Sample Preparation for Vitamin D Determination on a Biomek i7 Workstation

2021 ◽  
pp. 247263032110302
Author(s):  
Anna Bach ◽  
Heidi Fleischer ◽  
Bhagya Wijayawardena ◽  
Kerstin Thurow
Keyword(s):  
Vitamin D ◽  
Sample Preparation ◽  
Reference Method ◽  
Positive Pressure ◽  
Additional Risk Factor ◽  
Serum Samples ◽  
Recovery Rates ◽  
Preparation Methods ◽  
Sample Throughput ◽  
Automated Sample Preparation

Vitamin D belongs to the fat-soluble vitamins and is an integral part of bone metabolism. In the human body, a decreased vitamin D level can be an additional risk factor for diseases like cancer, diabetes, and mental diseases. As a result, an enormous increase in the demand for vitamin D testing has been observed in recent years, increasing the demand for powerful methods for vitamin D determination at the same time. Automation is the key factor in increasing sample throughput. This study compares three fully automated sample preparation methods for the determination of 25(OH)D2 and 25(OH)D3 in plasma and serum samples. Starting from a semiautomated reference method, the method is tested manually and subsequently fully automated on the Biomek i7 Workstation by integrating a centrifuge and a positive pressure extractor into the workstation. Alternatively, the centrifugation for the separation of protein aggregates and supernatant is replaced by a filter plate. Finally, the sample throughput is further increased by using phospholipid removal cartridges. The results show that phospholipid removal significantly increases the recovery rates in liquid chromatography–mass spectrometry. With the phospholipid removal cartridges, recovery rates of 97.36% for 25(OH)D2 and 102.5% for 25(OH)D3 were achieved, whereas with the automated classic automated preparation method, the recovery rates were 83.31% for 25(OH)D2 and 86.54% for 25(OH)D3. In addition to the technical evaluation, the different methods were also examined with regard to their economic efficiency. Finally, the qualitative and quantitative performance of the developed methods is benchmarked with a selected semiautomatic reference method.

scholarly journals COVID-19 Disease Severity and Death in Relation to Vitamin D Status among SARS-CoV-2-Positive UAE Residents

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1714
Author(s):  
Habiba AlSafar ◽  
William B. Grant ◽  
Rafiq Hijazi ◽  
Maimunah Uddin ◽  
Nawal Alkaabi ◽  
...  
Keyword(s):  
Vitamin D ◽  
United Arab Emirates ◽  
Blood Levels ◽  
Vitamin D Status ◽  
Hospital Visit ◽  
Serum Samples ◽  
Hydroxyvitamin D ◽  
Increased Risk ◽  
Multiethnic Population ◽  
25 Hydroxyvitamin D

Insufficient blood levels of the neurohormone vitamin D are associated with increased risk of COVID-19 severity and mortality. Despite the global rollout of vaccinations and promising preliminary results, the focus remains on additional preventive measures to manage COVID-19. Results conflict on vitamin D’s plausible role in preventing and treating COVID-19. We examined the relation between vitamin D status and COVID-19 severity and mortality among the multiethnic population of the United Arab Emirates. Our observational study used data for 522 participants who tested positive for SARS-CoV-2 at one of the main hospitals in Abu Dhabi and Dubai. Only 464 of those patients were included for data analysis. Demographic and clinical data were retrospectively analyzed. Serum samples immediately drawn at the first hospital visit were used to measure serum 25-hydroxyvitamin D [25(OH)D] concentrations through automated electrochemiluminescence. Levels < 12 ng/mL were significantly associated with higher risk of severe COVID-19 infection and of death. Age was the only other independent risk factor, whereas comorbidities and smoking did not contribute to the outcomes upon adjustment. Sex of patients was not an important predictor for severity or death. Our study is the first conducted in the UAE to measure 25(OH)D levels in SARS-CoV-2-positive patients and confirm the association of levels < 12 ng/mL with COVID-19 severity and mortality.

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