scholarly journals Development and Clinical Validation of a Sensitive Lateral Flow Assay for Rapid Urine Fentanyl Screening in the Emergency Department

2020 ◽  
Vol 66 (2) ◽  
pp. 324-332 ◽  
Author(s):  
Zhao Li ◽  
Hui Chen ◽  
Sheng Feng ◽  
Kengku Liu ◽  
Ping Wang
Keyword(s):  
Emergency Department ◽  
Sensitivity And Specificity ◽  
Point Of Care ◽  
Cross Reactivity ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Rapid Screening ◽  
Single Digit ◽  
Predictive Values ◽  
Clinical Sensitivity

Abstract Background Rapid identification of fentanyl at the point-of-care is critical. Urine fentanyl concentrations in overdose cases start at single-digit nanograms per milliliter. No fentanyl point-of-care assay with a cutoff at single-digit nanograms per milliliter is available. Methods A competitive lateral flow assay (LFA) was developed using gold nanoparticles and optimized for rapid screening of fentanyl in 5 minutes. Urine samples from 2 cohorts of emergency department (ED) patients were tested using the LFA and LC-MS/MS. The 2 cohorts consisted of 218 consecutive ED patients with urine drug-of-abuse screen orders and 7 ED patients with clinically suspected fentanyl overdose, respectively. Results The LFA detected fentanyl (≥1 ng/mL) and the major metabolite norfentanyl (≥10 ng/mL) with high precision. There was no cross-reactivity with amphetamine, cocaine, morphine, tetrahydrocannabinol, methadone, buprenorphine, naloxone, and acetaminophen at 1000 ng/mL and 0.03%, 0.4%, and 0.05% cross-reactivity with carfentanil, risperidone, and 9-hydroxyrisperidone, respectively. In 218 consecutive ED patients, the prevalence of cases with fentanyl ≥1 ng/mL or norfentanyl ≥10 ng/mL was 5.5%. The clinical sensitivity and specificity of the LFA were 100% (95% CI, 75.8–100%) and 99.5% (95% CI, 97.3–99.9%), respectively. The positive and negative predictive values were 92.3% (95% CI, 66.7–98.6%) and 100% (95% CI, 98.2–100%), respectively. The concordance between the LFA and LC-MS/MS was 100% in the 7 suspected fentanyl overdose cases (5 positive, 2 negative). Conclusions The LFA can detect fentanyl and norfentanyl with high clinical sensitivity and specificity in the ED population with rapid fentanyl screening needs.

scholarly journals Field evaluation of a prototype tuberculosis lipoarabinomannan lateral flow assay on HIV-positive and HIV-negative patients

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254156
Author(s):  
John T. Connelly ◽  
Alfred Andama ◽  
Benjamin D. Grant ◽  
Alexey Ball ◽  
Sandra Mwebe ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Point Of Care ◽  
Field Evaluation ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Hiv Positive ◽  
Clinical Sensitivity ◽  
Cell Counts ◽  
Significant Difference ◽  
Hiv Negative

Detection of tuberculosis at the point-of-care (POC) is limited by the low sensitivity of current commercially available tests. We describe a diagnostic accuracy field evaluation of a prototype urine Tuberculosis Lipoarabinomannan Lateral Flow Assay (TB-LAM LFA) in both HIV-positive and HIV-negative patients using fresh samples with sensitivity and specificity as the measures of accuracy. This prototype combines a proprietary concentration system with a sensitive LFA. In a prospective study of 292 patients with suspected pulmonary tuberculosis in Uganda, the clinical sensitivity and specificity was compared against a microbiological reference standard including sputum Xpert MTB/RIF Ultra and solid and liquid culture. TB-LAM LFA had an overall sensitivity of 60% (95%CI 51–69%) and specificity of 80% (95%CI 73–85%). When comparing HIV-positive (N = 86) and HIV-negative (N = 206) patients, there was no significant difference in sensitivity (sensitivity difference 8%, 95%CI -11% to +24%, p = 0.4351) or specificity (specificity difference -9%, 95%CI -24% to +4%, p = 0.2051). Compared to the commercially available Alere Determine TB-LAM Ag test, the TB-LAM LFA prototype had improved sensitivity in both HIV-negative (difference 49%, 95%CI 37% to 59%, p<0.0001) and HIV-positive patients with CD4+ T-cell counts >200cells/μL (difference 59%, 95%CI 32% to 75%, p = 0.0009). This report is the first to show improved performance of a urine TB LAM test for HIV-negative patients in a high TB burden setting. We also offer potential assay refinement solutions that may further improve sensitivity and specificity.

scholarly journals OC 8173 RAPID DETECTION OF MYCOBACTERIUM ULCERANS BY RECOMBINASE POLYMERASE AMPLIFICATION

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A2.1-A2
Author(s):  
Michael Frimpong ◽  
Hubert Ahor ◽  
Francisca Sarpong ◽  
Ken Laing ◽  
Mark Wansbrough-Jones ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Point Of Care ◽  
Clinical Signs ◽  
Buruli Ulcer ◽  
Cross Reactivity ◽  
Current Control ◽  
Mycobacterium Ulcerans ◽  
Recombinase Polymerase Amplification ◽  
Clinical Samples ◽  
Clinical Sensitivity

BackgroundThere are no primary measures to prevent people from contracting Buruli ulcer, mainly due to poor understanding of its epidemiology. The current control strategy emphasises early diagnosis and prompt treatment, with the goal of avoiding the complications associated with advanced stages of the disease. There is no diagnostic test for the disease appropriate for use at the primary health care level where most cases are detected and treated. Diagnosis based on clinical signs is unreliable in inexperienced hands and complicated by infections that have similar presentations. This study was to develop and evaluate the use of recombinase polymerase amplification (RPA) assay for the detection of Mycobacterium ulcerans at the point of patient care.MethodsA specific fragment of IS2404 of M. ulcerans was amplified in 15 min at a constant temperature of 42°C, using the RPA assay and analysed on a portable fluorometre. The’method was tested for sensitivity and specificity with molecular standard of IS2404 DNA fragment, various M.’ulcerans strains, other mycobacteria and environmentally associated bacteria. Additionally, the assay performance as a diagnostic tool was tested with archived DNA from symptomatic patients. All results were compared with that of a highly sensitive IS2404 PCR.ResultsThe detection limit was 50 copies of IS2404 in 15 min using plasmid standard and 125 fg with genomic Mu DNA equivalent 25 genomic copies. The assay was highly specific in detecting all strains of M. ulcerans with no observed cross reactivity with other mycobacteria and common skin colonising bacteria. The clinical sensitivity and specificity of the BU-RPA assay using clinical samples was 86% and 100% respectively.ConclusionWe have developed a real-time isothermal RPA assay for the detection of M. ulcerans as a cheaper alternative to PCR. Combining this assay with a simple extraction protocol will maximise its use as point-of-care test for Buruli ulcer.

A Point of Care Lateral Flow Assay for Rapid and Colorimetric Detection of Interleukin 6 and Perspectives in Bedside Diagnostics

2020 ◽  
Author(s):  
Carla Eiras
Keyword(s):  
Interleukin 6 ◽  
Limit Of Detection ◽  
Inflammatory Diseases ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Aggregation Assay ◽  
Before And After ◽  
Bedside Diagnosis

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM).The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.

A Point of Care Lateral Flow Assay for Rapid and Colorimetric Detection of Interleukin 6 and Perspectives in Bedside Diagnostics

2020 ◽  
Author(s):  
Carla Eiras
Keyword(s):  
Interleukin 6 ◽  
Limit Of Detection ◽  
Inflammatory Diseases ◽  
Point Of Care ◽  
Colorimetric Detection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Aggregation Assay ◽  
Before And After ◽  
Bedside Diagnosis

Interleukin-6 (IL-6) is a multifunctional cytokine and high bloodstream levels of which have been associated with severe inflammatory diseases, such as dengue fever, sepsis, various cancers, and visceral leishmaniasis (VL). Rapid tests for the quantification of IL-6 would be of great assistance for the bedside diagnosis and treatment of diseases such as VL. We have developed a lateral flow assay (LFA) for rapid and colorimetric IL-6 detection, consisting of anti-IL-6 antibodies conjugated to gold nanoparticles (AuNPs). The optimal concentration of anti-IL-6 used in the conjugate was determined to be 800.0 μg/mL, based on an aggregation assay using LFA. A linear relationship between IL-6 standard concentration and color intensity was observed after 20 min, with a linear range between 1.25 ng/mL and 9,000 ng/mL. The limit of detection for this method was estimated at a t0.38 ng/mL. The concentration of IL-6 in five patients with severe VL was measured using LFA, and the results were consistent with those obtained using the cytometric bead array (CBA) method. A thorough analysis of the LFA membranes’ surface morphology, before and after sample contact, was performed using atomic force microscopy (AFM). The prototype described here is still being tested and improved, but this LFA will undoubtedly be of great help in the clinical quantification of IL-6.

Lateral Flow Assay Based on Paper-Hydrogel Hybrid Material for Sensitive Point-of-Care Detection of Dengue Virus

2016 ◽  
Vol 6 (1) ◽  
pp. 1600920 ◽  
Author(s):  
Jane Ru Choi ◽  
Kar Wey Yong ◽  
Ruihua Tang ◽  
Yan Gong ◽  
Ting Wen ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Hybrid Material ◽  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Point Of Care Detection

scholarly journals Lateral flow assays for the detection of African swine fever virus antigen are not fit for field diagnosis of wild boar carcasses

2021 ◽  
Author(s):  
Paul Deutschmann ◽  
Jutta Pikalo ◽  
Martin Beer ◽  
Sandra Blome
Keyword(s):  
Wild Boar ◽  
Point Of Care ◽  
African Swine Fever ◽  
Virus Antigen ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Field Conditions ◽  
Real Field ◽  
Data Set ◽  
Field Samples

African swine fever (ASF) is one of the most important viral diseases of domestic pigs and wild boar. Apart from endemic cycles in Africa, ASF is now continuously spreading in Europe and Asia. As ASF leads to severe but unspecific clinical signs and high lethality, early pathogen detection is of utmost importance. Recently, “point-of-care” (POC) tests have been intensively discussed for the use in remote areas but also in the context of on-farm epidemiological investigations and wild boar carcass screening. Along these lines, the INGEZIM ASFV CROM Ag lateral flow assay (Eurofins Technologies Ingenasa) promises virus antigen detection under field conditions within minutes. In the present study, we evaluated the performance of the assay with selected high-quality reference blood samples, and also with real field samples from wild boar carcasses in different stages of decay from the ongoing ASF outbreak in Germany. While we observed a sensitivity of roughly 77% in freeze-thawed matrices of close to ideal quality, our approach to simulate field conditions in direct carcass testing without any modification resulted in a drastically reduced sensitivity of only 12.5%. Freeze thawing increased the sensitivity to roughly 44% which mirrored the overall sensitivity of 49% in the total data set of carcass samples. A diagnostic specificity of 100% was observed. However, most of the German ASF cases in wild boar would have been missed using the lateral flow assay (LFA) alone. Therefore, the antigen-specific LFA should not be regarded as a substitute for any OIE listed diagnostic method and has very limited use for carcass testing at the point of care. For optimized LFA antigen tests, the sensitivity with field samples must be significantly increased. An improved sensitivity is seen with freeze-thawed samples, which may indicate problems in the accessibility of ASFV antigen.

A Self-Contained Chemiluminescent Lateral Flow Assay for Point-of-Care Testing

2018 ◽  
Vol 90 (15) ◽  
pp. 9132-9137 ◽  
Author(s):  
Jinqi Deng ◽  
Mingzhu Yang ◽  
Jing Wu ◽  
Wei Zhang ◽  
Xingyu Jiang
Keyword(s):  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Point Of Care Testing

scholarly journals Performance of the Molecular Alere i Influenza A&B Test Compared to That of the Xpert Flu A/B Assay

2014 ◽  
Vol 53 (2) ◽  
pp. 706-709 ◽  
Author(s):  
Kimberle C. Chapin ◽  
Estefany J. Flores-Cortez
Keyword(s):  
Influenza Virus ◽  
Sensitivity And Specificity ◽  
Influenza A ◽  
Point Of Care ◽  
Type A ◽  
Influenza B ◽  
Clinical Sensitivity ◽  
Transport Medium ◽  
The Poor ◽  
B Test

Data on the performance of rapid molecular point-of-care use platforms for diagnosis of influenza are lacking. We validated nasopharyngeal (NP) flocked specimens in universal transport medium (UTM) and evaluated the clinical sensitivity and specificity of the Alere i influenza A&B test compared to those of the Xpert flu A/B assay. The Alere i influenza A&B test had an overall sensitivity and specificity of 93.8% and 62.5% for influenza A, respectively, and of 91.8% and 53.6% for influenza B, respectively. The poor specificity was due to influenza virus samples determined positive for both type A and B.

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