scholarly journals Evaluation of Production Lots of a Rapid Point-of-Care Lateral Flow Serological Test Intended for Identification of IgM and IgG against the N-Terminal Part of the Spike Protein (S1) of SARS-CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1043
Author(s):  
Tove Hoffman ◽  
Linda Kolstad ◽  
Bengt Rönnberg ◽  
Åke Lundkvist
Keyword(s):  
Predictive Value ◽  
Serological Test ◽  
Point Of Care ◽  
External Validation ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Spike Protein ◽  
Individual Level ◽  
Lateral Flow Test ◽  
Production Errors

The potential of rapid point-of-care (POC) tests has been subject of doubt due to an eventual risk of production errors. The aim was therefore to evaluate the two separate production lots of a commercial POC lateral flow test, intended for the detection of IgM and IgG against the SARS-CoV-2 spike protein (S1). Control samples consisted of serum from individuals with confirmed SARS-CoV-2 infection and pre-COVID-19 negative sera gathered from a biobank. The presence of anti-S1 IgM/IgG in the sera was verified by an in-house Luminex-based serological assay (COVID-19 SIA). One hundred samples were verified as positive for anti-S1 IgG and 74 for anti-S1 IgM. Two hundred samples were verified as negative for anti-S1 IgM/IgG. For the two lots of the POC-test, the sensitivities were 93.2% and 87.8% for IgM and 93.0% and 100% for IgG. The specificities were 100% for IgM and 99.5% for IgG. The positive predictive value was 100% for IgM and 98.9% and 99.0% for IgG. The negative predictive value was 97.6% and 95.7% for IgM, and 96.6% and 100% for IgG. The evaluated POC-test is suitable to assess anti-SARS-CoV-2 S1 IgM and IgG, as a measure of previous virus exposure on an individual level. The external validation of separate lots of rapid POC-tests is encouraged to ensure high sensitivity before market introduction.

scholarly journals Evaluation of production lots of a rapid point-of-care lateral flow serological test intended for identification of IgM and IgG against the N-terminal part of the spike protein (S1) of SARS-CoV-2

2020 ◽  
Author(s):  
Tove Hoffman ◽  
Linda Kolstad ◽  
Bengt Ronnberg ◽  
Ake Lundkvist
Keyword(s):  
Predictive Value ◽  
Serological Test ◽  
Point Of Care ◽  
External Validation ◽  
Rapid Test ◽  
Reference Method ◽  
Spike Protein ◽  
Index Test ◽  
Rt Pcr ◽  
Terminal Part

Background and objectives: Several antibody tests are available to detect SARS-CoV-2 specific antibodies, many of which address different antigens. Rapid point-of-care (POC) tests have been doubted due to an eventual risk of production errors, although it is unstudied whether such error would affect test sensitivity and/or specificity. We aimed to evaluate two separate production lots of a commercially available test intended for rapid detection of IgM and IgG against the N-terminal part of the SARS-CoV-2 spike protein (S1). Materials and methods: Serum samples from individuals with confirmed SARS-CoV-2 infection, by RT-PCR and/or serology, and pre-COVID-19 negative control sera gathered from a biobank during 2018 were collected. The presence of anti-S1 IgM/IgG was verified by an in-house Luminex-based serological assay, serving as reference method. The index test was a commercially available rapid POC-test (the COVID-19 IgG/IgM Rapid Test Cassette [Zhejiang Orient Gene Biotech Co Ltd, Huzhou, Zhejiang, China/Healgen Scientific, LLC, U.S.A.]). Results: One hundred samples were verified positive for anti-S1 IgG (median fluorescence intensity (MFI) greater than or equal to 900) and 74 for anti-S1 IgM (MFI greater than or equal to 700), confirmed by RT-PCR (n=90) and/or serology (n=89). None of the negative controls (n=200; MFI <300) had SARS-CoV-2 anti-S1 IgM, while one tested positive for SARS-CoV-2 anti-S1 IgG. For the two lots, the sensitivities of the rapid test were 93.2% (69/74; 95% CI: 85.1% - 97.1%) and 87.8% (65/74; 95% CI: 78.5% - 93.5%) for IgM, respectively 93.0% (93/100; 95% CI: 86.3% - 96.6%) and 100.0% for IgG (100/100; 95% CI: 96.3% - 100.0%). The specificity for both lots was 100% for IgM (200/200; 95% CI: 98.1% - 100%) and 99.5% for IgG (199/200; 95% CI: 97.2% - 99.9%). The positive predictive value was 100% for IgM and 98.9% and 99.0% for IgG. The negative predictive value was 95.7% and 97.6% for IgM, and 96.6% and 100.0% for IgG. Conclusion: The rapid POC-test used in this study is suitable to assess SARS-CoV-2 anti-S1 specific IgM/IgG, as a measure of previous virus exposure on an individual level. While the specificity was not affected by production lot, external validation of separate lots of rapid POC-tests is encouraged to ensure high sensitivity before market introduction.

scholarly journals Integrating high-performing electrochemical transducers in lateral flow assay

2021 ◽  
Author(s):  
Antonia Perju ◽  
Nongnoot Wongkaew
Keyword(s):  
High Performance ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Analytical Performance ◽  
Label Free ◽  
High Performing ◽  
Lateral Flow Assays ◽  
Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

Point-Of-Care Clinical Evaluation of the Clungene® SARS-CoV-2 Virus IgG/IgM 15-minute rapid test cassette with the Cobas® Roche RT-PCR platform in patients with or without Covid-19

2021 ◽  
Author(s):  
Fadi Haddad ◽  
Christopher C Lamb ◽  
Ravina Kullar ◽  
George Sakoulas
Keyword(s):  
Symptom Onset ◽  
Serological Test ◽  
Point Of Care ◽  
Diagnostic Testing ◽  
Rapid Test ◽  
Lateral Flow ◽  
Added Value ◽  
Lateral Flow Immunoassay ◽  
Rt Pcr ◽  
Past Infection

Background: Covid-19 remains a pandemic with multiple challenges to confirm patient infectivity: lack of sufficient tests, accurate results, validated quality, and timeliness of results. We hypothesize that a rapid 15-minute Point-Of-Care serological test to evaluate past infection complements diagnostic testing for Covid-19 and significantly enhances testing availability. Method: A three arm observational study at Sharp Healthcare, San Diego, California was conducted using the Clungene® lateral flow immunoassay (LFI) and compared with the Cobas® Roche RT PCR results. Arm 1: Thirty-five (35) subjects with confirmed Covid-19 using RT-PCR were tested twice: prior to 14 days following symptom onset and once between 12 and 70 days. Arm 2: Thirty (30) subjects with confirmed Covid-19 using RT-PCR were tested 12-70 days post symptom onset. Arm 3: Thirty (30) subjects with a negative RT-PCR for Covid-19 were tested 1-10 days following the RT-PCR test date. Results: Specificity of confirmed negative Covid-19 by RT-PCR was 100% (95% CI, 88.4%-100.0%); meaning there was 100% negative positive agreement between the RT-PCR and the Clungene® serological test results. Covid-19 subjects tested prior to day 7 symptom onset were antibody negative. In subjects 7-12 days following symptom onset with a confirmed positive Covid-19 by RT-PCR, the combined sensitivity of IgM and IgG was 58.6% (95% CI, 38.9%-76.5%). In subjects 13-70 days following symptom onset with a confirmed positive Covid-19 by RT-PCR the combined sensitivity of IgM and IgG was 90.5% (95% CI, 80.4%-96.4%). Conclusion: The Clungene® lateral flow immunoassay (LFI) is a useful tool to confirm individuals with an adaptive immune response to SARS-CoV-2 indicating past infection. Providing Point-Of-Care results within 15 minutes without any laboratory instrumentation or specialized software has an added value of increasing test availability to patients who have been symptomatic for more than one week to confirm past infection. Performance characteristics are optimal after 13 days with a sensitivity and specificity of 90% and 100%, respectively.

scholarly journals The SARS-COV-2 Spike Protein Binds Sialic Acids and Enables Rapid Detection in a Lateral Flow Point of Care Diagnostic Device

2020 ◽  
Vol 6 (11) ◽  
pp. 2046-2052 ◽  
Author(s):  
Alexander N. Baker ◽  
Sarah-Jane Richards ◽  
Collette S. Guy ◽  
Thomas R. Congdon ◽  
Muhammad Hasan ◽  
...  
Keyword(s):  
Rapid Detection ◽  
Point Of Care ◽  
Sialic Acids ◽  
Lateral Flow ◽  
Spike Protein ◽  
Diagnostic Device

scholarly journals Evaluation of a rapid lateral flow calprotectin test for the diagnosis of prosthetic joint infection

2019 ◽  
Author(s):  
Alexander J. Trotter ◽  
Rachael Dean ◽  
Celia E. Whitehouse ◽  
Jarle Mikalsen ◽  
Claire Hill ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Sensitivity And Specificity ◽  
Prosthetic Joint Infection ◽  
Predictive Value ◽  
Joint Infection ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Prosthetic Joint ◽  
Flow Test ◽  
Lateral Flow Test

AbstractBackgroundMicrobiological diagnosis of prosthetic joint infection (PJI) relies on culture techniques that are slow and insensitive. Rapid tests are urgently required to improve patient management. Calprotectin is a neutrophil biomarker of inflammation that has been demonstrated to be effective for the diagnosis of PJI. A calprotectin based lateral flow test has been developed for the rapid detection of PJI using synovial fluid samples.MethodsA convenience series of 69 synovial fluid samples from patients at the Norfolk and Norwich University Hospitals (NNUH) were collected intraoperatively from 52 hip and 17 knee revision operations. Calprotectin levels were measured using a new commercially available lateral flow assay for PJI diagnosis (Lyfstone). For all samples, synovial fluid was pipetted onto the lateral flow device and the signal was read using a mobile phone app after 15 minutes incubation at room temperature.ResultsAccording to the Musculoskeletal Infection Society (MSIS) criteria, 24 patients were defined as PJI positive and the remaining 45 were negative. The overall accuracy of the lateral flow test against the MSIS criteria was 75%. The test had a sensitivity and specificity of 75% and 76% respectively with a positive predictive value (PPV) of 62% and a negative predictive value (NPV) of 85%. Discordant results were then reviewed by the clinical team using available patient data to develop an alternative gold standard for defining presence/absence of infection (MSIS+). Compared to MSIS+, the test showed an overall accuracy of 83%, sensitivity and specificity of 95% and 78% respectively, a PPV of 62% and an NPV of 98%. Test accuracy for hip revisions was 77% and for knee revisions was 100%.ConclusionsThis study demonstrates that the calprotectin lateral flow assay is an effective diagnostic test for PJI. Our data suggests that the test is likely to generate false positive results in patients with metallosis and gross osteolysis.

scholarly journals TUBERCULOUS PERICARDITIS AND PLEURITIS;

2017 ◽  
Vol 24 (05) ◽  
pp. 656-664
Author(s):  
Hamid Mahmood ◽  
Talmeez Zaib ◽  
Zafar Hayat Maken ◽  
Ammara Waqar ◽  
Yasir Hassan ◽  
...  
Keyword(s):  
Negative Predictive Value ◽  
Predictive Value ◽  
Point Of Care ◽  
High Sensitivity ◽  
Smear Microscopy ◽  
Diagnostic Validity ◽  
Standard Material ◽  
Point Of Care Test ◽  
Resource Limited ◽  
Attractive Point

Background: Diagnosis of Tubercles Pericarditis and Pleuritis remains thegreatest challenge for clinicians. WHO has recommended GeneXpert MTB/RIF assay as ascreening test for substitution of conventional methods for the initial diagnosis and prognosisof the extra pulmonary and pulmonary tuberculosis in developing countries. Objectives: Tofind out the diagnostic validity of GeneXpert assay for detection of Myco-bacterium tuberculosisin the pericardial and pleural effusions samples, keeping MTB culture as “Gold Standard”.Material and Methods: Total number of 286 samples of effusions (pericardial 128, pleural 158)were received, and processed for Zn smear microscopy, LJ culture, GeneXpert MTB/RIF assayaccording standard protocols. Efficacy for the detection of MTB was evaluated comparatively.Results: Out of 286effusions samples AFB was detected by Zn smear in 11 (3.8%) samples whileGeneXpert detected MTB in 43 (15.0%) and LJ culture 51 (17.8%). Zn smear showed sensitivity18.2%, specificity, 98.1%, Positive predictive value 81.8%, Negative predictive value 85.4 %, incomparison GeneXpert showed high sensitivity 84.3%, specificity 100%, with Positive predictivevalue 100%, and Negative predictive value 96.7%. Conclusion: GeneXpert assay is innovativetool in resource limited settings for prompt detection of MTB along with drug résistance. It isdefinitely an attractive point of care test, with High sensitivity and specificity along with turnouttime of two hours which facilitates timely diagnoses and appropriate management of tuberclePleuritis and Pericarditis.

scholarly journals Clinical Evaluation of a COVID-19 Antibody Lateral Flow Assay using Point of Care Samples

2020 ◽  
Author(s):  
Won Lee ◽  
Steven Straube ◽  
Ryan Sincic ◽  
Jeanne A. Noble ◽  
Juan Carlos Montoy ◽  
...  
Keyword(s):  
Predictive Value ◽  
Point Of Care ◽  
Acute Infection ◽  
High Specificity ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Onset Date ◽  
Rt Pcr ◽  
Serum Samples ◽  
Antibody Positivity

ABSTRACTIntroductionThe ongoing SARS-CoV-2 pandemic has spurred the development of numerous point of care (PoC) immunoassays. Assessments of performance of available kits are necessary to determine their clinical utility. Previous studies have mostly performed these assessments in a laboratory setting, which raises concerns of translating findings for PoC use. The aim of this study was to assess the performance of a lateral flow immunoassay for the detection of SARS-CoV-2 antibodies using samples collected at PoC.MethodOne lateral flow immunoassay (Humasis® COVID-19 IgG/IgM) was tested. In total, 50 PCR RT-PCR positive and 52 RT-PCR negative samples were collected at PoC. Fifty serum specimens from Dec 2018 to Feb 2019 were used as controls for specificity. Serum samples collected between Dec 2019 to Feb 2020 were used as additional comparators. Clinical data including symptom onset date was collected from patient history and the medical record.ResultsThe overall sensitivity for the kit was 74% (95% CI: 59.7% -85.4%). The sensitivity for IgM and IgG detection >14 days after date of onset was 88% (95% CI: 68.8% -97.5%) and 84% (95% CI: 63.9% – 95.5%), with a negative predictive value (NPV) of 94% for IgM (95% CI: 83.5% - 98.8%) and 93% for IgG (95% CI: 81.8% - 97.9%). The overall specificity was 94% (95% CI: 83.5% - 98.8%). The Immunoglobulin specific specificity was 94% for IgM (95% CI: 83.5% - 98.8%) and 98% for IgG (95% CI: 89.4% - 100.0%), with a positive predictive value (PPV) of 88% for IgM (95% CI: 68.8% - 97.5%) and 95% for IgG (95% CI: 77.2% - 99.9%) respectively for samples collected from patients >14 days after date of onset. Specimen collected during early phase of COVID-19 pandemic (Dec 2019 to Feb 2020) showed 11.8% antibody positivity, and 11.3% of PCR-negative patients demonstrated antibody positivity.DiscussionHumasis® COVID-19 IgG/IgM LFA demonstrates greater than 90% PPV and NPV for samples collected 14 days after the onset of symptoms using samples collected at PoC. While not practical for the diagnosis of acute infection, the use of the lateral flow assays with high specificity may have utility for determining seroprevalence or seroconversion in longitudinal studies.

Diagnostic ability of salivary matrix metalloproteinase‐9 lateral flow test point‐of‐care test for periodontitis

2020 ◽  
Vol 47 (11) ◽  
pp. 1354-1361
Author(s):  
Hyun‐Duck Kim ◽  
Chang‐Soo Lee ◽  
Hyun‐Jae Cho ◽  
Sumin Jeon ◽  
Young‐Nim Choi ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Point Of Care ◽  
Test Point ◽  
Matrix Metalloproteinase 9 ◽  
Lateral Flow ◽  
Diagnostic Ability ◽  
Point Of Care Test ◽  
Flow Test ◽  
Lateral Flow Test ◽  
Metalloproteinase 9

scholarly journals Comparison of Point-of-Care Ultrasonography and Radiography in the Diagnosis of Long-Bone Fractures

Medicina ◽  
2019 ◽  
Vol 55 (7) ◽  
pp. 355 ◽  
Author(s):  
Avci ◽  
Kozaci ◽  
Tulubas ◽  
Caliskan ◽  
Yuksel ◽  
...  
Keyword(s):  
Predictive Value ◽  
Bone Fractures ◽  
Point Of Care ◽  
High Sensitivity ◽  
Long Bone ◽  
Imaging Method ◽  
Fracture Characteristics ◽  
Point Of Care Ultrasonography ◽  
Sensitivity Specificity

Background and objectives: In this study, the accuracy of point-of-care ultrasonography (POCUS) was compared to radiography (XR) in the diagnosis of fractures, the determination of characteristics of the fractures, and treatment selection of fractures in patients admitted to the emergency department (ED) due to trauma and suspected long bone (LB) fractures. Materials and Methods: The patients were included in the study, who were admitted to ED due to trauma, and had physical examination findings suggesting the presence of fractures in LB (humerus, radius, ulna, femur, tibia, and fibula). The patients were evaluated by two emergency physicians (EP) in ED. The first EP examined LBs with POCUS and the second EP examined them with XR. LBs were evaluated on the anterior, posterior, medial, and lateral surfaces and from the proximal joint to the distal one (shoulder, elbow, wrist, hip, knee, and ankle joint) in both longitudinal and transverse axes with POCUS. Results: A total of 205 patients with suspected LB fractures were included in the study. LB fractures were determined in 99 patients with XR and in 105 patients with POCUS. The sensitivity, specificity, positive predictive value, negative predictive value of POCUS in determining the fractures were 99%, 93%, 93%, and 99%, respectively, compared to XR. Compared to XR, POCUS was able to determine 100% of fissure type fractures (kappa (κ) value: 0.765), 83% of linear fractures (κ: 0.848), 92% of fragmented fractures(κ: 0.756), 67% of spiral fractures (κ:0.798), 75% of avulsion type fractures (κ: 0.855), and 100% of full separation type fractures (κ: 0.855).Conclusions: This study has demonstrated that POCUS has a high sensitivity in diagnosing LB fractures. POCUS has a high sensitivity in identifying fracture characteristics. POCUS can be used as an alternative imaging method to XR in the diagnosis of LB fractures and in the determination of fracture characteristics.

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