scholarly journals Laboratory Diagnostic Techniques for Entamoeba Species

2007 ◽  
Vol 20 (3) ◽  
pp. 511-532 ◽  
Author(s):  
R. Fotedar ◽  
D. Stark ◽  
N. Beebe ◽  
D. Marriott ◽  
J. Ellis ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Diagnostic Tests ◽  
New Technologies ◽  
Specific Antigen ◽  
Gastrointestinal Symptoms ◽  
Public Health Problem ◽  
Intestinal Lumen ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Diagnostic Laboratory

SUMMARY The genus Entamoeba contains many species, six of which (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba polecki, Entamoeba coli, and Entamoeba hartmanni) reside in the human intestinal lumen. Entamoeba histolytica is the causative agent of amebiasis and is considered a leading parasitic cause of death worldwide in humans. Although recent studies highlight the recovery of E. dispar and E. moshkovskii from patients with gastrointestinal symptoms, there is still no convincing evidence of a causal link between the presence of these two species and the symptoms of the host. New approaches to the identification of E. histolytica are based on detection of E. histolytica-specific antigen and DNA in stool and other clinical samples. Several molecular diagnostic tests, including conventional and real-time PCR, have been developed for the detection and differentiation of E. histolytica, E. dispar, and E. moshkovskii in clinical samples. The purpose of this review is to discuss different methods that exist for the identification of E. histolytica, E. dispar, and E. moshkovskii which are available to the clinical diagnostic laboratory. To address the need for a specific diagnostic test for amebiasis, a substantial amount of work has been carried out over the last decade in different parts of the world. The molecular diagnostic tests are increasingly being used for both clinical and research purposes. In order to minimize undue treatment of individuals infected with other species of Entamoeba such as E. dispar and E. moshkovskii, efforts have been made for specific diagnosis of E. histolytica infection and not to treat based simply on the microscopic examination of Entamoeba species in the stool. The incorporation of many new technologies into the diagnostic laboratory will lead to a better understanding of the public health problem and measures to control the disease.

Molecular Diagnostics

2019 ◽  
Author(s):  
Duncan Clark ◽  
Mark Wilks
Keyword(s):  
Nucleic Acid ◽  
Molecular Diagnostics ◽  
Diagnostic Tests ◽  
Clinical Sample ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Acid Extraction ◽  
Molecular Test ◽  
Block Based ◽  
Set Up

Molecular diagnostics in infection generally relate to the detection and/ or characterization of nucleic acid sequences of infectious agents in clinical samples which are used to provide: ● A laboratory diagnosis. ● A means of monitoring patients at risk of developing disease caused by a particular infection. ● A method to predict through genotypic analysis the susceptibility or resistance to appropriate treatments. ● A measurement of the response to therapy. A few key laboratory techniques underpin the majority of molecular diagnostic tests that are currently used in the field of infection, and include: ● Block-based polymerase chain reaction (PCR). ● Real-time PCR, including quantification. ● Strand displacement amplification. ● Transcription mediated amplification. ● DNA sequencing. These can be commercially sourced, which has the advantage of CE marking, or developed in-house, sometimes referred to as laboratory developed tests (LDTs). Whatever the source, the underlying principles are often the same and rigorous evaluation and validation is required for the adoption of any molecular test in the diagnostic laboratory. The majority of molecular diagnostic tests require the amplification of a specific DNA sequence and its subsequent detection by a variety of means. As such, small sequences of DNA from the infectious agent are amplified from a relatively low copy number in the clinical sample. For example, after thirty to forty cycles of PCR, a single copy of a sequence can theoretically be amplified to over a billion copies. This PCR product, commonly termed amplicon, can provide a template for any further testing with the same PCR test and therefore potentially act as a source for false positive results. Molecular diagnostic laboratories have requirements to keep the different stages of the molecular test separate and minimize the risk of amplicon contamination. Most facilities will have a ‘clean PCR laboratory’ that is used to store the clean reagents such as primers, probes, enzyme mastermixes, and no clinical samples, nucleic extracts, or amplification reactions are ever taken into this environment. Another laboratory is used for the nucleic acid extraction of the clinical samples and this environment is often used to set up the PCR reactions.

scholarly journals A One-Step open RT-qPCR for SARS-CoV-2 detection

2021 ◽  
Author(s):  
Ariel Cerda ◽  
Maira Rivera ◽  
Grace Armijo ◽  
Catalina Ibarra-Henriquez ◽  
Javiera Reyes ◽  
...  
Keyword(s):  
Open Source ◽  
Dna Polymerase ◽  
Quantitative Polymerase Chain Reaction ◽  
Diagnostic Errors ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Diagnostic Laboratory ◽  
Taq Dna Polymerase ◽  
One Step ◽  
Current Context

AbstractThe Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), etiological agent of the coronavirus disease 2019 (COVID-19), is currently detected by reverse transcription followed by quantitative polymerase chain reaction (RT-qPCR) of its viral RNA genome. Within the available alternatives, One-Step procedures are preferred since they are fast and significantly decrease preanalytical errors, minimizing the risk of diagnostic errors.Increasing the testing capacity and tracing contacts are essential steps to control the pandemic. However, high-cost commercial reagents subject to shortage and poor scalability have hindered the use of these technologies and their adoption for a wide population-scale testing, being even more critical in developing countries. In the current context, open-source initiatives have promoted global collaboration to promote accessible solutions for rapid local deployment. As a result, open protocols are being developed for the local production of SARS-CoV-2 diagnostics.This work aimed to produce an open-source system for SARS-CoV-2 diagnostic tests in RNA clinical samples. We provide guidelines for standardizing an open One-Step RT-qPCR master mix using recombinant M-MLV reverse transcriptase together with either Pfu-Sso7d or Taq DNA polymerase. Both were tested on synthetic RNA and clinical samples, observing a good correlation when compared to commercial RT-qPCR kits. Nevertheless, the best results were obtained using M-MLV RT combined with Taq DNA polymerase in a probe-based RT-qPCR assay, allowing successful discrimination between positive and negative samples with accuracies comparable to a CDC-recommended commercial kit.Here, we demonstrate that these open RT-qPCR systems can be successfully used to identify SARS-CoV-2 in clinical samples and potentially be implemented in any molecular diagnostic laboratory.

scholarly journals Advances in Environmental Detection and Clinical Diagnostic Tests for Legionella Species

2021 ◽  
Author(s):  
Rajeshwari Vittal ◽  
Juliet Roshini Mohan Raj ◽  
Ballamoole Krishna Kumar ◽  
Indrani Karunasagar
Keyword(s):  
Developing Countries ◽  
Healthcare System ◽  
Diagnostic Tests ◽  
Clinical Manifestations ◽  
Cost Effective ◽  
Clinical Samples ◽  
Detection Techniques ◽  
Conventional Culture ◽  
Legionella Species ◽  
Mild Fever

Abstract Legionella is a fastidious organism that is difficult to culture in the lab but is widely distributed in environmental, domestic, and hospital settings. The clinical manifestations due to Legionella infections range from mild fever to fatal pneumonia and multiorgan pathologies. Legionella outbreaks though prevalent globally are not reported in developing countries due to difficulties in isolating this organism and the lack of simple diagnostic protocols. Here, we review the literature from across countries to present various methods used to detect Legionella from environmental and clinical samples. We compare the sensitivity and the specificity of the conventional culture-based assays with the recent methods and discuss approaches to develop better detection and diagnostic tests. With better cost-effective detection techniques and regular monitoring of the susceptible sites, which may harbor Legionella colonies, most of the Legionella infections can be prevented. As a result, considerable burden, caused by Legionella infections, on the healthcare system, in especially economically weaker countries, can be mitigated.

scholarly journals Implementation of Rapid Molecular Diagnostic Tests and Antimicrobial Stewardship Involvement in Acute-Care Hospitals

2020 ◽  
Vol 41 (S1) ◽  
pp. s278-s279
Author(s):  
Maiko Kondo ◽  
Matthew Simon ◽  
Esther Babady ◽  
Angela Loo ◽  
David Calfee
Keyword(s):  
Antimicrobial Stewardship ◽  
Diagnostic Tests ◽  
New Technology ◽  
Clinical Care ◽  
Bloodstream Infections ◽  
Clinical Decision ◽  
Research Network ◽  
Molecular Diagnostic ◽  
Financial Outcomes ◽  
Stewardship Program

Background: In recent years, several rapid molecular diagnostic tests (RMDTs) for infectious diseases diagnostics, such as bloodstream infections (BSIs), have become available for clinical use. The extent to which RMDTs have been adopted and how the results of these tests have been incorporated into clinical care are currently unknown. Methods: We surveyed members of the Society for Healthcare Epidemiology of America Research Network to characterize utilization of RMDT in hospitals and antimicrobial stewardship program (ASP) involvement in result communication and interpretation. The survey was administered using Qualtrics software, and data were analyzed using Stata and Excel software. Results: Overall, 57 responses were received (response rate, 59%), and 72% were from academic hospitals; 50 hospitals (88%) used at least 1 RMDT for BSI (Fig. 1). The factors most commonly reported to have been important in the decision to adopt RMDT were improvements in antimicrobial usage (82%), clinical outcomes (74%), and laboratory efficiency (52%). Among 7 hospitals that did not use RMDT for BSI, the most common reason was cost of new technology. In 50 hospitals with RMDT for BSI, 54% provided written guidelines for optimization or de-escalation of antimicrobials based upon RMDT results. In 40 hospitals (80%), microbiology laboratories directly notified a healthcare worker of the RMDT results: 70% provided results to a physician, nurse practitioner, or physician assistant; 48% to the ASP team; and 33% to a nurse. Furthermore, 11 hospitals (22%) had neither guidelines nor ASP intervention. In addition, 24 hospitals (48%) reported performing postimplementation evaluation of RMDT impact. Reported findings included reduction in time to antibiotic de-escalation (75%), reduction in length of stay (25%), improved laboratory efficiency (20%), and reduction in mortality and overall costs (12%). Among the 47 hospitals with both RMDT and ASP, 79% reported that the ASP team routinely reviewed blood culture RMDT results, and 53.2% used clinical decision support software to do so. Finally, 53 hospitals (93%) used 1 or more RMDT for non–bloodstream infections (Fig. 1). Fewer than half of hospitals provided written guidelines to assist clinicians in interpreting these RMDT results. Conclusions: RMDTs have been widely adopted by participating hospitals and are associated with positive self-reported clinical, logistic, and financial outcomes. However, nearly 1 in 4 hospitals did not have guidelines or ASP interventions to assist clinicians with optimization of antimicrobial prescribing based on RMDT results for BSI. Also, most hospitals did not have guidelines for RMDT results for non-BSI. These findings suggest that opportunities exist to further enhance the potential benefits of RMDT.Funding: NoneDisclosures: None

scholarly journals DNA aptamer-based detection of prostate cancer

2015 ◽  
Vol 69 (1) ◽  
Author(s):  
Pawan Jolly ◽  
Nello Formisano ◽  
Pedro Estrela
Keyword(s):  
Prostate Cancer ◽  
Point Of Care ◽  
Specific Antigen ◽  
Analytical Techniques ◽  
Cost Effective ◽  
Dna Aptamer ◽  
Clinical Samples ◽  
Gradual Transition ◽  
Long Term Stability ◽  
Promising Tool

AbstractThe use of aptamers in biosensing has attracted considerable attention as an alternative to antibodies because of their unique properties such as long-term stability, cost-effectiveness and adjustability to various applications. Among cancers, the early diagnosis of prostate cancer (PCa) is one of the greatest concerns for ageing men worldwide. One of the most commonly used biomarkers for PCa is prostate-specific antigen (PSA), which can be found in elevated levels in patients with cancer. This review presents the gradual transition of research from antibody-based to aptamerbased biosensors, specifically for PSA. A brief description on aptamer-based biosensing for other PCa biomarkers is also presented. Special attention is given to electrochemical methods as analytical techniques for the development of simple, sensitive and cost-effective biosensors. The review also focuses on the different surface chemistries exploited for fabrication and their applications in clinical samples. The use of aptamers represents a promising tool for the development of point-ofcare biosensors for the early detection of prostate cancer. In view of the unmatched upper hand of aptamers, future prospects are also discussed, not only in the point-of-care format but also in other novel applications.

scholarly journals LAMP in Neglected Tropical Diseases: A Focus on Parasites

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 521
Author(s):  
Juan García-Bernalt Diego ◽  
Pedro Fernández-Soto ◽  
Antonio Muro
Keyword(s):  
Neglected Tropical Diseases ◽  
Treatment Success ◽  
Public Health Problem ◽  
Nucleic Acid Amplification ◽  
Molecular Diagnostic ◽  
Diagnostic Tools ◽  
World Population ◽  
Major Public Health Problem ◽  
Tropical Diseases ◽  
Early 21St Century

Neglected Tropical Diseases (NTDs), particularly those caused by parasites, remain a major Public Health problem in tropical and subtropical regions, with 10% of the world population being infected. Their management and control have been traditionally hampered, among other factors, by the difficulty to deploy rapid, specific, and affordable diagnostic tools in low resource settings. This is especially true for complex PCR-based methods. Isothermal nucleic acid amplification techniques, particularly loop-mediated isothermal amplification (LAMP), appeared in the early 21st century as an alternative to PCR, allowing for a much more affordable molecular diagnostic. Here, we present the status of LAMP assays development in parasite-caused NTDs. We address the progress made in different research applications of the technique: xenomonitoring, epidemiological studies, work in animal models and clinical application both for diagnosis and evaluation of treatment success. Finally, we try to shed a light on the improvements needed to achieve a true point-of-care test and the future perspectives in this field.

Analysis of the tendency of development of biosensors based on GaN

2021 ◽  
Author(s):  
S.I. Agasieva ◽  
E.A. Smetanin ◽  
A.R. Vechkanov ◽  
A.V. Gubanov
Keyword(s):  
Clinical Trials ◽  
Infectious Diseases ◽  
Diagnostic Tests ◽  
Diagnostic Testing ◽  
Healthcare Systems ◽  
Clinical Analysis ◽  
Molecular Diagnostic ◽  
Economic Damage ◽  
Disease Research ◽  
Local Healthcare

Statement of the problem of this article - one of the most important problems is protection from especially dangerous infectious diseases. The use of biosensors in clinical trials will significantly reduce the time for obtaining the results of analyzes, thereby speeding up the appointment of treatment to patients. The purpose of the article is to present modern designs of biosensors based on gallium nitride, the possibilities of their application and characteristics. Consider the principles of operation, areas of application and characteristics. As a result, the design of modern biosensors and modern trends in their use from various sources of literature in recent years are shown. Biosensors, principles of their action, areas of application and characteristics are considered, which will reduce the possible socio-economic damage from temporary disability for sick citizens due to the rapid and timely implementation of anti-epidemic measures. Practical value: the proposed biosensors are of interest as devices for detecting diseases. The use of biosensors in clinical disease research has several potential advantages over other clinical analysis methods, including increased analysis speed and flexibility, multipurpose analysis capability, automation, reduced diagnostic testing costs, and the ability to integrate molecular diagnostic tests into local healthcare systems.

scholarly journals Performance of the 4Kscore Test in Plasma and Serum and Stability of the Component Analytes in Clinical Samples

2018 ◽  
Vol 3 (2) ◽  
pp. 185-199 ◽  
Author(s):  
Christina E Higgins ◽  
Patricia Neybold ◽  
Marcella B Holdridge ◽  
Catherine R Barnes ◽  
Yan Dong ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Specific Antigen ◽  
Clinical Information ◽  
Target Population ◽  
Clinical Samples ◽  
Free Psa ◽  
Total Prostate Specific Antigen ◽  
Edta Plasma ◽  
The Stability ◽  
Intact Psa

Abstract Background The 4Kscore Test determines a personalized risk score for aggressive prostate cancer by combining the blood sample measurements of total prostate-specific antigen (tPSA), free PSA (fPSA), intact PSA (iPSA), and human kallikrein-related peptidase 2 (hK2) with patient clinical information to generate the patient risk's score; thus, accuracy and precision of the 4Kscore depend on the reliability of these measurements. Although tPSA and fPSA are measured on a Food and Drug Administration (FDA)-approved platform, the performance of the iPSA and hK2 assays in the clinical setting has not previously been reported. Methods Analytical performance was determined for the iPSA and hK2 assays in both serum and EDTA plasma, according to Clinical and Laboratory Standards Institute guidelines. Equivalence of the 4Kscore in both sample matrices was demonstrated in a 353-patient clinical cohort, and the stability of endogenous iPSA and hK2 for at least 3 days was demonstrated in a smaller subset. Results Intralaboratory and interlaboratory precision of the iPSA and hK2 assays in both matrices was comparable with that of FDA-approved tPSA and fPSA assays (<18% for iPSA; <8% for hK2). The picogram per milliliter sensitivity and wide dynamic range of the iPSA and hK2 assays allowed for accurate measurements in the target population. The 4Kscore generated in either matrix up to 3 days after collection is equivalent to that measured within 24 h of collection (Passing–Bablok slope 95% CI: plasma, 0.999–1.034; serum, 0.997–1.040). Conclusions The robust performance of component assays and reliable stability of the endogenous analytes in clinical samples proven here ensures an accurate 4Kscore Test result.

A point-of-care diagnostic for differentiating Ebola from endemic febrile diseases

2018 ◽  
Vol 10 (471) ◽  
pp. eaat0944 ◽  
Author(s):  
David Sebba ◽  
Alexander G. Lastovich ◽  
Melody Kuroda ◽  
Eric Fallows ◽  
Joshua Johnson ◽  
...  
Keyword(s):  
Ebola Virus ◽  
Clinical Symptoms ◽  
Point Of Care ◽  
Hemorrhagic Fever ◽  
Diagnostic Methods ◽  
Outbreak Detection ◽  
Molecular Diagnostic ◽  
Clinical Samples ◽  
Live Virus ◽  
And Control

Hemorrhagic fever outbreaks such as Ebola are difficult to detect and control because of the lack of low-cost, easily deployable diagnostics and because initial clinical symptoms mimic other endemic diseases such as malaria. Current molecular diagnostic methods such as polymerase chain reaction require trained personnel and laboratory infrastructure, hindering diagnostics at the point of need. Although rapid tests such as lateral flow can be broadly deployed, they are typically not well-suited for differentiating among multiple diseases presenting with similar symptoms. Early detection and control of Ebola outbreaks require simple, easy-to-use assays that can detect and differentiate infection with Ebola virus from other more common febrile diseases. Here, we developed and tested an immunoassay technology that uses surface-enhanced Raman scattering (SERS) tags to simultaneously detect antigens from Ebola, Lassa, and malaria within a single blood sample. Results are provided in <30 min for individual or batched samples. Using 190 clinical samples collected from the 2014 West African Ebola outbreak, along with 163 malaria positives and 233 negative controls, we demonstrated Ebola detection with 90.0% sensitivity and 97.9% specificity and malaria detection with 100.0% sensitivity and 99.6% specificity. These results, along with corresponding live virus and nonhuman primate testing of an Ebola, Lassa, and malaria 3-plex assay, indicate the potential of the SERS technology as an important tool for outbreak detection and clinical triage in low-resource settings.

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