scholarly journals Evaluation of the Dynamiker Cryptococcal Antigen Lateral Flow Assay for the Diagnosis of HIV-Associated Cryptococcosis

2020 ◽  
Author(s):  
Richard Kwizera ◽  
Denis Omali ◽  
Kiiza Tadeo ◽  
John Kasibante ◽  
Morris K. Rutakingirwa ◽  
...  
Keyword(s):  
Predictive Value ◽  
Diagnostic Performance ◽  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Sub Saharan Africa ◽  
Serum Samples ◽  
Cryptococcal Antigen ◽  
Asymptomatic Patients ◽  
Sub Saharan

Background: Cryptococcal meningitis is a leading cause of meningitis in sub-Saharan Africa. Given the need for rapid point of care testing, we evaluated the diagnostic performance of the Dynamiker cryptococcal antigen (CrAg) lateral flow assay (LFA). Methods: We assessed the diagnostic performance of the Dynamiker CrAg-LFA compared to the IMMY CrAg-LFA as the reference standard. We tested 150 serum, 115 plasma, 100 cerebrospinal fluid (CSF) samples from HIV patients with symptomatic meningitis and 113 serum samples from patients with suspected asymptomatic cryptococcal antigenemia. Results: Compared to the IMMY CrAg-LFA, sensitivity of Dynamiker CrAg-LFA was 98% in serum, 100% in plasma, 100% in CSF from symptomatic patients and 96% in serum from asymptomatic patients. Specificity was 66% in serum, 61% in plasma, 91% in CSF from symptomatic patients, and 86% in serum from asymptomatic patients. The positive predictive value was 85% in serum, 82% in plasma, 96% in CSF from symptomatic patients, and 69% in serum from asymptomatic patients. The negative predictive value was 94% in serum, 100% in plasma, 100% in CSF from symptomatic patients, and 99% in serum from asymptomatic patients. The inter-assay reproducibility was 100% across the four sample types with no observed discordant results when Dynamiker CrAg-LFA was tested in duplicate. However, a high number of false positives were observed on serum of symptomatic patients (11%), serum of asymptomatic patients (11%) and plasma of symptomatic patients (14%). Conclusion: The Dynamiker CrAg-LFA had excellent sensitivity but poor specificity, particularly when tested on serum and plasma.

scholarly journals Development of a Novel Cocktail Enzyme-Linked Immunosorbent Assay and a Field-Applicable Lateral-Flow Rapid Test for Diagnosis of Contagious Bovine Pleuropneumonia

2016 ◽  
Vol 54 (6) ◽  
pp. 1557-1565 ◽  
Author(s):  
Martin Heller ◽  
Nimmo Gicheru ◽  
Georgina Tjipura-Zaire ◽  
Cecilia Muriuki ◽  
Mingyan Yu ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Rapid Test ◽  
Lateral Flow ◽  
Sub Saharan Africa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Contagious Bovine Pleuropneumonia ◽  
Serum Samples ◽  
Content Type ◽  
Mycoplasma Mycoides ◽  
Sub Saharan

Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease that is widespread in sub-Saharan Africa. It is caused byMycoplasma mycoidessubsp.mycoides, a bacterium belonging to theMycoplasma mycoidescluster. In the absence of an efficient CBPP vaccine, improved and easy-to-use diagnostic assays for recurrent testing combined with isolation and treatment of positive animals represent an option for CBPP control in Africa. Here we describe the comprehensive screening of 17 immunogenicMycoplasma mycoidessubsp.mycoidesproteins using well-characterized bovine sera for the development of a novel cocktail enzyme-linked immunosorbent assay (ELISA) for laboratory use. Two recombinantMycoplasmaimmunogens, MSC_0136 and MSC_0636, were used to set up a standardized cocktail ELISA protocol. According to the results from more than 100 serum samples tested, the sensitivity and specificity of the novel cocktail ELISA were 85.6% and 96.4%, respectively, with an overall diagnostic accuracy comparable to that of the Office International des Epizooties (OIE)-prescribed serological assays. In addition, we provide a proof of principle for a field-applicable, easy-to-use commercially produced prototype lateral-flow test for rapid (<30-min) diagnosis of CBPP.

The cryptococcal antigen lateral flow assay: A point-of-care diagnostic at an opportune time

2015 ◽  
Vol 42 (4) ◽  
pp. 634-642 ◽  
Author(s):  
Michele W. Tang ◽  
Karl V. Clemons ◽  
David A. Katzenstein ◽  
David A. Stevens
Keyword(s):  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Cryptococcal Antigen ◽  
Opportune Time

Towards malaria microscopy at the point-of-contact: an assessment of the diagnostic performance of the Newton Nm1 microscope in Uganda

Parasitology ◽  
2014 ◽  
Vol 141 (14) ◽  
pp. 1819-1825 ◽  
Author(s):  
J. RUSSELL STOTHARD ◽  
BETTY NABATTE ◽  
JOSE C. SOUSA-FIGUEIREDO ◽  
NARCIS B. KABATEREINE
Keyword(s):  
Confidence Interval ◽  
Positive Predictive Value ◽  
Predictive Value ◽  
Blood Cells ◽  
Diagnostic Performance ◽  
White Blood Cells ◽  
Sub Saharan Africa ◽  
Resource Poor ◽  
Sub Saharan ◽  
Malaria Microscopy

SUMMARYMalaria microscopy in sub-Saharan Africa is often restricted by access to light microscopes. To address this gap, a novel portable inverted monocular microscope, the Newton Nm1, was designed and is now commercially available. Its diagnostic performance was assessed in a blinded-slide trial at ×1000 (oil) of Giemsa-stained thick blood films against a conventional microscope as undertaken by four Ugandan Ministry of Health technicians. With the Newton Nm1, diagnostic performance was: sensitivity 93·5% (95% confidence interval (CI) 78·6–99·2%), specificity 100·0% (95% CI 82·4–100·0%), positive predictive value 100·0% (95% CI 88·1–100·0%) and negative predictive value 90·5% (95% CI 69·6–98·8%). Discordance was due to a systematic error underestimating parasitaemia by ~45%; when counting Plasmodium parasites against 200 white blood cells, blood films with low parasitaemia (i.e. <100 μL−1 of blood) could be overlooked and misclassified. By contrast, specificity was excellent with no false positives encountered. Whilst proven useful, especially in resource-poor environments, it is still unclear how we can ensure the uptake of the Newton Nm1 within sub-Saharan Africa.

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.

scholarly journals Point-of-Care Diagnosis and Prognostication of Cryptococcal Meningitis With the Cryptococcal Antigen Lateral Flow Assay on Cerebrospinal Fluid

2013 ◽  
Vol 58 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Taseera Kabanda ◽  
Mark J. Siedner ◽  
Jeffrey D. Klausner ◽  
Conrad Muzoora ◽  
David R. Boulware
Keyword(s):  
Cerebrospinal Fluid ◽  
Cryptococcal Meningitis ◽  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Cryptococcal Antigen

scholarly journals Cryptococcal antigen prevalence in HIV-infected Tanzanians: a cross-sectional study and evaluation of a point-of-care lateral flow assay

2013 ◽  
Vol 18 (9) ◽  
pp. 1075-1079 ◽  
Author(s):  
Joan Rugemalila ◽  
Venance P. Maro ◽  
Gibson Kapanda ◽  
Arnold J. Ndaro ◽  
Joseph N. Jarvis
Keyword(s):  
Point Of Care ◽  
Cross Sectional Study ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Sectional Study ◽  
Cross Sectional ◽  
Cryptococcal Antigen

scholarly journals Diagnosis of Cryptococcosis and Prevention of Cryptococcal Meningitis Using a Novel Point-of-Care Lateral Flow Assay

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Ashar Dhana
Keyword(s):  
Cryptococcal Meningitis ◽  
Point Of Care ◽  
World Health Organisation ◽  
Lateral Flow ◽  
Sub Saharan Africa ◽  
World Health ◽  
First Case ◽  
Lateral Flow Dipstick ◽  
Life Threatening ◽  
Sub Saharan

Despite access to antiretroviral therapy, mortality from cryptococcal meningitis (CM) is high among persons with advanced HIV infection in sub-Saharan Africa. Cryptococcal antigen (CrAg) is present several weeks to months before the onset of symptoms of meningitis and can be screened to prevent life threatening meningitis. Recently, the World Health Organisation recommended that a new rapid CrAg lateral flow ‘‘dipstick’’ assay (LFA) is to be used to screen HIV-infected persons with CD4 counts of less than 100 cells/µL. In this paper, we describe two cases of cryptococcosis with differing outcomes. In the first case, the new CrAg LFA was used as part of a screen and preemptive treatment strategy to prevent CM. In the second case, our patient had no access to the CrAg LFA and subsequently developed life threatening meningitis. To the best of our knowledge, this is the first case report of cryptococcosis diagnosed using this novel assay.

Evaluation of a commercially available, point-of-care Coccidioides antibody lateral flow assay to aid in rapid diagnosis of coccidioidomycosis in dogs

2019 ◽  
Vol 58 (3) ◽  
pp. 328-332 ◽  
Author(s):  
Sallianne Schlacks ◽  
Polina Vishkautsan ◽  
Christine Butkiewicz ◽  
Lisa Shubitz
Keyword(s):  
Point Of Care ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Reference Laboratory ◽  
Serum Samples ◽  
Percent Agreement ◽  
Life Threatening Illness ◽  
Life Threatening ◽  
Paired Serum ◽  
High Level

Abstract Coccidioidomycosis in dogs can range from mild respiratory disease or vague, chronic malaise to acute, severe life-threatening illness. The diagnosis of coccidioidomycosis in dogs is based on clinical presentation and serology. Spherule identification is not typical because of low numbers of organisms in specimens, and the invasive nature of sampling tissues and lungs. Conventional serological assays require samples to be submitted to a reference laboratory and results take several days to one week. The sōna Coccidioides Antibody Lateral Flow Assay (LFA) (IMMY Diagnostics) is a rapid, bench-side test used for detection of Coccidioides antibodies that is available and FDA-cleared for use in humans but has not been evaluated in dogs. The goal of this study was to compare the LFA to conventional agar gel immunodiffusion (AGID). Paired serum samples were collected for screening by the LFA and submitted to a commercial reference laboratory for AGID screen and titer. Of 56 paired serum samples analyzed, 30 were positive and 26 were negative on the sōna Coccidioides antibody LFA. The overall percentage agreement plus 95% confidence interval (CI) was 87.5% (76.20–93.99). Positive percent agreement was 89.7% (73.38–96.65) and negative percent agreement was 85.2% (67.25–94.36). The kappa coefficient to assess agreement was 0.749 (95% CI, 0.576–0.923), which is interpreted as good agreement between the tests (&gt;70%). The sōna Coccidioides antibody LFA provided rapid, point-of-care results with a high level of agreement to standard AGID serology in dogs clinically suspected to have coccidioidomycosis, and may aid in diagnosis of coccidioidomycosis in dogs.

scholarly journals Evaluation of a cryptococcal antigen lateral flow assay test for rapid detection of cryptococcal infection in HIV-negative patients in Ibadan, Nigeria

2021 ◽  
Vol 22 (1) ◽  
pp. 93-96
Author(s):  
S.A. Fayemiwo ◽  
O.B. Makanjuola ◽  
J. Nwaokenye ◽  
M.O. Owolabi
Keyword(s):  
Diagnostic Accuracy ◽  
Predictive Value ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Likelihood Ratios ◽  
Cryptococcal Antigen ◽  
Cryptococcal Infection ◽  
Test Kit ◽  
Sensitivity Specificity ◽  
Hiv Negative

Background: A number of studies have been conducted in Nigeria on the prevalence of cryptococcal infections mostly on HIV-infected patients using culture, India ink and/or latex agglutination tests. These tests are either laborious, time-consuming and expensive or have low sensitivity, thus limiting their use. Cryptococcal antigen lateral flow assays (LFA) were introduced in the last decade as rapid user-friendly tests for diagnosis. In this study, we sought to determine the diagnostic accuracy of an LFA kit for the detection of cryptococcal antigen in the serum of HIV-negative patients with or without cerebrovascular accident (CVA) or stroke in University College Hospital, Ibadan, Nigeria.Methodology: The diagnostic accuracy of Dynamiker CrAg LFA was tested against BiosynexR CryptoPS on serum samples of 100 HIV-negative patients with and without stroke. Samples were tested and results interpreted in accordance with the manufacturer’s instructions. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios of the Dynamiker CrAg LFA were calculated by comparing with the BiosynexR CryptoPS as ‘gold standard’.Results: Overall, a total of 98 valid patient sample results were analysed; 17 samples (17.3%) were positive with Dynamiker CrAg LFA cryptococcal antigen and 16 samples (16.3%) were positive with BiosynexR CryptoPS. The sensitivity, specificity, PPV and NPV of Dynamiker CrAg LFA compared to the BiosynexR CryptoPS were 100%, 98.8%, 94.1% and 100% respectively, while the positive and negative likelihood ratios were 82 and 0 respectively.Conclusion: In comparison to the BiosynexR CryptoPS, the Dynamiker CrAg LFA is a highly sensitive and specific test for the detection of cryptococcal antigen in serum. The test kit should be considered as a screening device for cryptococcal infection both in outreach and clinical settings, especially in antiretroviral therapy (ART) centres. Keywords: Cryptococcus; evaluation; lateral flow assay; HIV-negative; stroke

scholarly journals Laboratory diagnosis of human brucellosis in Egypt and persistence of the pathogen following treatment

2011 ◽  
Vol 5 (11) ◽  
pp. 786-791 ◽  
Author(s):  
Ayman Marei ◽  
Ghada Boghdadi ◽  
Nahla Abdel-Hamed ◽  
Rasha Hessin ◽  
Theresia Abdoel ◽  
...  
Keyword(s):  
Point Of Care ◽  
Public Health Problem ◽  
Laboratory Diagnosis ◽  
Diagnostic Value ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Human Brucellosis ◽  
Major Public Health Problem ◽  
Serum Samples ◽  
Point Of Care Test

Introduction: Brucellosis is a major public health problem in Egypt. The Brucella IgM/IgG lateral flow assay was developed as a point-of-care test for the diagnosis of human brucellosis. The aim of this study was to assess the diagnostic value of the lateral flow assay for use in Egypt. Methodology: Fifty samples of patients who presented with clinical suspicion of brucellosis over a one-year period were collected.  All samples were subjected to the Brucella IgM/IgG lateral flow assay, serum agglutination test (SAT), rose bengal RB Test (RB), 2- mercapteoethanol (2-ME), culture and PCR. SAT, 2- ME, culture and PCR were retested after the end of the treatment. Results: Culture and SAT confirmed the diagnosis of brucellosis in twenty patients.  While 90% of the samples were positive by SAT, only 30% and 85% were positive by culture and PCR respectively. The sensitivity of the lateral flow assay calculated for the Brucella IgM/IgG was 95% and specificity was 97%. Conclusion: These data show that the lateral flow assay is more suitable for diagnosis of brucellosis in Egypt than culture and SAT.  Application of the PCR on serum samples collected during follow-up revealed that the DNA of the pathogen was yet not completely cleared almost 60 days after the start of treatment with doxycycline and ciprofloxacin.

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