scholarly journals A comparative evaluation of three methods for the rapid diagnosis of cryptococcal meningitis (CM) among HIV-infected patients in Northern Malawi

2020 ◽  
Vol 32 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Master Chisale
Keyword(s):  
Diagnostic Tests ◽  
Target Population ◽  
Rapid Diagnosis ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Diagnostic Methods ◽  
Gram Stain ◽  
Cross Sectional ◽  
Timely Initiation ◽  
India Ink

IntroductionCryptococcal meningitis (CM) is the most common systemic fungal infection in patients with HIV infection. Rapid diagnosis and timely initiation of antifungal therapy are key to reducing mortality rate associated with CM. This study aims to evaluate the ability of four different diagnostic tests (Gram stain, India ink, and two types of commercial lateral flow assay [LFA]) to identify CM-positive patients and to compare the sensitivity and specificity of these tests.MethodsThis was a prospective cross-sectional study on diagnostic tests accuracy conducted in Northern Malawi. The target population was HIV-infected adult patients presenting with features of meningitis. Four types of diagnostic tests were conducted: India ink, Gram stain, and two types of commercial lateral flow assay (LFA) (Immy, Inc., OK, USA and Dynamiker Biotechnology (Tianjin) Co., Ltd), Singapore). Culture was conducted as the reference standard.ResultsA total of 265 samples were collected. The rate of positive CM detection ranged from 6.4% (using India ink) to 14.3% (using LFA). India ink exhibited the lowest sensitivity of 54.8% (95% confidence interval [CI]: 36.0%–72.7%), followed by Gram stain (61.3%; 95% CI: 42.2%–78.2%). The Dynamiker LFA exhibited the highest sensitivity of 100.0% (95% CI: 90.0%–100.0%) but a lower specificity (97.0%; 93.9%–98.8%) compared to the Immy LFA (98.3%; 95% CI: 95.7%–99.5%). ConclusionLFA diagnostic methods have the potential to double the detection rate of CM-positive patients in resource-limited countries such as Malawi. As such, LFAs should be considered to become the main diagnostic tests used for CM diagnostics in these countries. Our data indicate that LFAs may be the best method for diagnosing CM and exhibits the highest diagnostic accuracy as it has shown that it outperforms cell culture, the current gold standard.

What are the best diagnostic tests for diagnosing bacterial arthritis of a native joint?

2021 ◽  
Vol 103-B (12) ◽  
pp. 1745-1753
Author(s):  
Alex B. Walinga ◽  
Tobias Stornebrink ◽  
David W. G. Langerhuizen ◽  
Peter A. A. Struijs ◽  
Gino M. M. J. Kerkhoffs ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Diagnostic Tests ◽  
High Specificity ◽  
Diagnostic Methods ◽  
Youden Index ◽  
Polymorphonuclear Cells ◽  
Gram Stain ◽  
Bacterial Arthritis ◽  
Diagnostic Modality ◽  
Serum Crp

Aims This study aimed to answer two questions: what are the best diagnostic methods for diagnosing bacterial arthritis of a native joint?; and what are the most commonly used definitions for bacterial arthritis of a native joint? Methods We performed a search of PubMed, Embase, and Cochrane libraries for relevant studies published between January 1980 and April 2020. Of 3,209 identified studies, we included 27 after full screening. Sensitivity, specificity, area under the curve, and Youden index of diagnostic tests were extracted from included studies. We grouped test characteristics per diagnostic modality. We extracted the definitions used to establish a definitive diagnosis of bacterial arthritis of a native joint per study. Results Overall, 28 unique diagnostic tests for diagnosing bacterial arthritis of a native joint were identified. The following five tests were deemed most useful: serum ESR (sensitivity: 34% to 100%, specificity: 23% to 93%), serum CRP (sensitivity: 58% to 100%, specificity: 0% to 96%), serum procalcitonin (sensitivity: 0% to 100%, specificity: 68% to 100%), the proportion of synovial polymorphonuclear cells (sensitivity: 42% to 100%, specificity: 54% to 94%), and the gram stain of synovial fluid (sensitivity: 27% to 81%, specificity: 99% to 100%). Conclusion Diagnostic methods with relatively high sensitivities, such as serum CRP, ESR, and synovial polymorphonuclear cells, are useful for screening. Diagnostic methods with a relatively high specificity, such as serum procalcitonin and synovial fluid gram stain, are useful for establishing a diagnosis of bacterial arthritis. This review helps to interpret the value of various diagnostic tests for diagnosing bacterial arthritis of a native joint in clinical practice. Cite this article: Bone Joint J 2021;103-B(12):1745–1753.

scholarly journals Identification of Mycoses in Developing Countries

2019 ◽  
Vol 5 (4) ◽  
pp. 90 ◽  
Author(s):  
Amir Arastehfar ◽  
Brian L. Wickes ◽  
Macit Ilkit ◽  
David H. Pincus ◽  
Farnaz Daneshnia ◽  
...  
Keyword(s):  
Developing Countries ◽  
Real Time ◽  
Real Time Pcr ◽  
Fungal Infections ◽  
Point Of Care ◽  
Fungal Species ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Diagnostic Methods ◽  
Diagnostic Tools

Extensive advances in technology offer a vast variety of diagnostic methods that save time and costs, but identification of fungal species causing human infections remains challenging in developing countries. Since the echinocandins, antifungals widely used to treat invasive mycoses, are still unavailable in developing countries where a considerable number of problematic fungal species are present, rapid and reliable identification is of paramount importance. Unaffordability, large footprints, lack of skilled personnel, and high costs associated with maintenance and infrastructure are the main factors precluding the establishment of high-precision technologies that can replace inexpensive yet time-consuming and inaccurate phenotypic methods. In addition, point-of-care lateral flow assay tests are available for the diagnosis of Aspergillus and Cryptococcus and are highly relevant for developing countries. An Aspergillus galactomannan lateral flow assay is also now available. Real-time PCR remains difficult to standardize and is not widespread in countries with limited resources. Isothermal and conventional PCR-based amplification assays may be alternative solutions. The combination of real-time PCR and serological assays can significantly increase diagnostic efficiency. However, this approach is too expensive for medical institutions in developing countries. Further advances in next-generation sequencing and other innovative technologies such as clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostic tools may lead to efficient, alternate methods that can be used in point-of-care assays, which may supplement or replace some of the current technologies and improve the diagnostics of fungal infections in developing countries.

Rapid diagnosis of tuberculosis in dromedary camel (Camelus dromedarius) using lateral flow assay-based kit

2017 ◽  
Vol 50 (4) ◽  
pp. 907-910 ◽  
Author(s):  
Rakesh Ranjan ◽  
Shirish D. Narnaware ◽  
Kashi Nath ◽  
R. K. Sawal ◽  
N. V. Patil
Keyword(s):  
Rapid Diagnosis ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Camelus Dromedarius ◽  
Dromedary Camel

Development of a recombinase polymerase amplification (RPA-EXO) and lateral flow assay (RPA-LFA) based on the ITS1 gene for the detection of Angiostrongylus cantonensis in gastropod intermediate hosts

Parasitology ◽  
2020 ◽  
pp. 1-8
Author(s):  
Susan I. Jarvi ◽  
Elizabeth S. Atkinson ◽  
Lisa M. Kaluna ◽  
Kirsten A. Snook ◽  
Argon Steel
Keyword(s):  
Lateral Flow ◽  
Angiostrongylus Cantonensis ◽  
Lateral Flow Assay ◽  
Diagnostic Methods ◽  
Qpcr Assay ◽  
Recombinase Polymerase Amplification ◽  
Intermediate Hosts ◽  
Infection Level ◽  
Specialized Equipment ◽  
The Central Nervous System

Abstract Angiostrongylus cantonensis is a parasitic nematode known to infect humans through the ingestion of third stage larvae which can cause inflammation and damage to the central nervous system. Currently, polymerase chain reaction (PCR) is one of the most reliable diagnostic methods for detecting A. cantonensis in humans as well as in gastropod hosts, but requires expensive and specialized equipment. Here, we compare the sensitivity and accuracy of a recombinase polymerase amplification Exo (RPA-EXO) assay, and a recombinase polymerase amplification lateral flow assay (RPA-LFA) with a traditional quantitative PCR (qPCR) assay currently available. The three assays were used to test 35 slugs from Hawai‘i for the presence of A. cantonensis DNA. Consistent results among the three tests were shown in 23/35 samples (65.7%), while 7/35 (20%) were discordant in low infection level samples (<0.01 larvae per mg tissue), and 5/35 (14.3%) were equivocal. To evaluate sensitivity, a partial ITS1 gene was cloned, and serial plasmid dilutions were created ranging from 100 copies μL−1 to ~1 copy μL−1. All three assays consistently detected 50–100 copies μL−1 in triplicate and qPCR was able to detect ~13 copies μL−1 in triplicate. RPA-EXO was able to detect 25 copies μL−1 in triplicate and RPA-LFA was not able to amplify consistently below 50 copies μL−1. Thus, our RPA-EXO and RPA-LFA assays do not appear as sensitive as the current qPCR assay at low DNA concentrations; however, these tests have numerous advantages that may make them useful alternatives to qPCR.

scholarly journals Effective Diagnosis of Foot-And-Mouth Disease Virus (FMDV) Serotypes O and A Based on Optical and Electrochemical Dual-Modal Detection

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 841
Author(s):  
Yun-Jung Hwang ◽  
Kyung-Kwan Lee ◽  
Jong-Won Kim ◽  
Kwang-Hyo Chung ◽  
Sang-Jick Kim ◽  
...  
Keyword(s):  
Disease Virus ◽  
Foot And Mouth Disease ◽  
Lateral Flow ◽  
Mouth Disease ◽  
Lateral Flow Assay ◽  
Diagnostic Methods ◽  
Fmdv Serotypes ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
Fmdv Type

Foot-and-mouth disease virus (FMDV) is a highly contagious disease that affects cloven-hoofed animals. The traditional diagnostic methods for FMDV have several drawbacks such as cross-reactivity, low sensitivity, and low selectivity. To overcome these drawbacks, we present an optical and electrochemical dual-modal approach for the specific detection of FMDV serotypes O and A by utilizing a magnetic nanoparticle labeling technique with resorufin β-d-glucopyranoside (res-β-glc) and β-glucosidase (β-glc), without the use of typical lateral flow assay or polymerase chain reaction. FMDV serotypes O and A were reacted with pan-FMDV antibodies that recognize all seven FMDV serotypes (O, A, C, Asia 1, SAT 1, SAT 2, and SAT 3). The antigen–antibody complex was then immobilized on magnetic nanoparticles and reacted with β-glc-conjugated FMDV type O or type A antibodies. Subsequently, the addition of res-β-glc resulted in the release of fluorescent resorufin and glucose owing to catalytic hydrolysis by β-glc. The detection limit of fluorescent signals using a fluorescence spectrophotometer was estimated to be log(6.7) and log(5.9) copies/mL for FMDV type O and A, respectively, while that of electrochemical signals using a glucometer was estimated to be log(6.9) and log(6.1) copies/mL for FMDV type O and A, respectively. Compared with a commercially available lateral flow assay diagnostic kit for immunochromatographic detection of FMDV type O and A, this dual-modal detection platform offers approximately four-fold greater sensitivity. This highly sensitive and accurate dual-modal detection method can be used for effective disease diagnosis and treatment, and will find application in the early-stage diagnosis of viral diseases and next-generation diagnostic platforms.

scholarly journals 257. Aspergillus Galactomannan Lateral Flow Assay for Rapid Diagnosis of Invasive Aspergillosis in Bronchoalveolar Lavage

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S143-S143
Author(s):  
Martin Hoenigl ◽  
Sharon L Reed ◽  
Sanjay R Mehta ◽  
Nancy Law ◽  
Saima Aslam ◽  
...  
Keyword(s):  
Bronchoalveolar Lavage ◽  
Hematological Malignancies ◽  
Invasive Pulmonary Aspergillosis ◽  
Rapid Test ◽  
Lavage Fluid ◽  
Rapid Diagnosis ◽  
Lateral Flow ◽  
Lateral Flow Assay ◽  
Lower Specificity ◽  
Neutropenic Patients

Abstract Background Early diagnosis and treatment of invasive pulmonary aspergillosis (IPA) remain the most important factor to reduce mortality. Diagnosis remains a challenge, however, due to unspecific clinical presentation and radiological findings. Only very recently rapid tests for IPA have been developed. The objective of this study was to evaluate the performance of the new CE-marked Aspergillus Galactomannan Lateral Flow Assay (LFA; IMMY, Oklahoma, USA; figure) for IPA in patients with and without hematological malignancies. Methods The Aspergillus Galactomannan LFA was retrospectively performed according to the manufacturer’s instructions in 106 previously frozen bronchoalveolar lavage fluid (BAL) samples from 106 patients at risk for IPA (23% with underlying hematological malignancies). Samples were collected between September 2016 and September 2018 at the University of California, San Diego. Performance of the LFA was compared with Galactomannan, BAL culture and the Aspergillus-specific LFD (another rapid test for IPA). IPA was classified according to revised EORTC/MSG criteria. Results Overall, 22 patients met criteria of probable or proven IPA, 9 possible IPA, while 75 patients did not fulfill criteria of IPA. Sensitivity of the Apergilllus Galactomanann LFA for probable/proven IPA was 77% (17/22). Sensitivity was similar to BAL GM (77% with a cutoff of 1.0 ODI), but higher compared with the Aspergillus-specific LFD (59%), and BAL culture (23%). The LFA resulted negative in 7/9 cases with possible IPA and 47/73 cases without IPA (overall specificity 66%, 54/82). The less than perfect specificity was driven particularly by non-neutropenic patients (specificity 62%, 43/69), while specificity was 85% among patients with underlying hematological malignancies. Lower specificity among non-neutropenic patients was also observed for the BAL GM (overall 77%, non-neutropenic patients 72%), the Aspergillus-specific LFD (overall 70%, non-neutropenic patients 67%) and BAL culture (overall 90%, non-neutropenic 88%). Conclusion Our study indicates that the LFA may be useful for rapid diagnosis of IPA in BALF when IPA is clinically suspected. The lower specificity in non-neutropenic patients may be explained by limited applicability of the EORTC/MSG criteria in those patients. Disclosures All authors: No reported disclosures.

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