Polymerase Chain Reaction (PCR) has significantly helped in early diagnosis and commencement of specific interventions for diseases control. It also plays a critical role in understanding the disease epidemiology and unraveling the transmission dynamics of the disease. This manual intends to p...rovide primary guidelines to assist health lab personnel in developing countries to establish a PCR diagnostic facility for efficient support to patient care as well as public health actions.
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This clinical job aid provides health care workers with information on how to collect specimens for early infant diagnosis on dried blood spots, as well as drying and packaging for transport.
Protocol and preliminary evaluationas of Jan 17, 2020
Interium guidance, 25 June 2021Timely and accurate diagnostic testing is an essential tool in preventing and controlling the spread of COVID-19. This document describes recommendations for national testing strategies and the use of PCR and rapid antigen tests in different transmission scenarios of t...he COVID-19 outbreak, including how testing might be rationalized in low resource settings. All testing should be followed by a strong public health response including isolating those who test positive and providing them care, contact tracing and quarantine of contacts.
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Many in-house and commercial assays that detect the COVID-19 virus have been developed or are currently under development. Many of these molecular assays are currently being validated in partner laboratories. An overview of assays that have applied to FIND for participation in their assay assessment... work can be found here
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FIND is collating an overview of SARS-CoV-2 tests that are commercially available or in development for the diagnosis of COVID-19. We do not guarantee that this is a comprehensive list, since the information below has been submitted voluntarily by test suppliers and is not independently verified. Pl...ease find the latest lists on the website
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A total of 18 laboratories from 13 countries participated in the four rounds of EQA: 10 laboratories from eight African endemic countries, four of which participated in all four rounds and three in three rounds. The overall results showed that the median performance of these laboratories improved ov...er the four rounds. However, the proportion of laboratories reporting false–positive cases remains high and indicates a problem of specificity probably due to contamination. The proportion of laboratories reporting both false–positive and false–negative results raises the issue of the quality of the data reported by WHO in Africa as well as the results of the studies carried out in these different laboratories in various countries.
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Im Kapitel zu Diagnostik zum Nachweis von COVID-19 bekommen Sie ausführlich die verschiedenen Testmethoden erklärt, es können Videos zu PCR, RAchenabstrich, etc. aufgerufen werden
Limited coverage of laboratory services and long turnaround times from real-time reverse transcription-polymerase chain reaction (rRT-PCR) for the detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been insufficient to meet the demands in many African countries in response... to the COVID-19 pandemic. Rapid antigen diagnostic tests (AgRDTs) are potentially useful as they can inform healthcare workers and individuals of their infection status at point-of-care testing
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Guide de recommandations rapides 11 juin 2020
Depuis son identification en Chine en décembre 2019, le nouveau coronavirus responsable de la COVID‐19 s’est rapidement propagé pour causer une pandémie. Cette maladie se manifeste par des symptômes respiratoires non spécifiques de gravité var...iable et peut nécessiter une assistance respiratoire importante. Son diagnostic est actuellement confirmé grâce l’identification de l’ARN du virus grâce à un test de laboratoire utilisant la technique de la transcription inverse-amplification génique (en anglais, reverse transcriptase polymerase chain reaction, soit RT-PCR.
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Any individual that meets the suspected case definition of monkeypox should be offered testing in appropriately equipped laboratories by staff trained in the relevant technical and safety procedures. Confirmation of monkeypox virus infection is based on nucleic acid amplification testing (NAAT), usi...ng real-time or conventional polymerase chain reaction (PCR), for detection of unique sequences of viral DNA. PCR can be used alone, or in combination with sequencing. The recommended specimen type for laboratory confirmation of monkeypox is skin lesion material, including swabs of lesion surface and/or exudate, roofs from more than one lesion, or lesion crusts.
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Buruli ulcer is caused by infection with Mycobacterium ulcerans. The disease is reported in more than 33 countries worldwide, but only about half of these countries regularly report data to WHO; most cases are reported from subregions of West and Central Africa. The mode of transmission is not known....
About half of those affected are children aged under 15 years; there is no gender difference. Diagnosis is based mainly on clinical and epidemiological characteristics. Of the four methods used for laboratory confirmation (microscopy, polymerase chain reaction (PCR), histopathology and culture), PCR is the most rapid and widely used. Other rapid methods for detection of mycolactone in lesions from suspected cases, such as fluorescent thin-layer chromatography, are under evaluation in four countries in Africa.
Research to develop point-of-care tests is in progress. Treatment of Buruli ulcer comprises 8 weeks of combined antibiotics (rifampicin and clarithromycin). Complementary therapies such as wound care, skin graft and prevention of disability are needed in some cases to ensure full recovery.
The target set by the World Health Organization (WHO) for control of Buruli ulcer is for countries to achieve a rate of case confirmation by PCR of at least 70%. All endemic countries have at least one PCR facility to support confirmation of cases. However, most countries in the WHO African Region have not been able to reach the target, and the rate of case confirmation has been declining
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L’ulcère de Buruli, une infection causée par Mycobacterium ulcerans, touche plus de 33 pays dans le monde, mais un peu moins de la moitié seulement de ces pays communiquent régulièrement des données sur la maladie à l’OMS. La plupart des cas notifiés se trouvent dans les sous-régions d...Afrique occi-
dentale et centrale. Le mode de transmission de l’ulcère de Buruli n’est pas connu. Environ la moitié des personnes touchées sont des enfants de moins de 15 ans et les deux sexes sont concernés à parts égales.
Le diagnostic repose principalement sur l’observation des caractéristiques cliniques et épidémiologiques.
Parmi les quatre méthodes de confirmation utilisées (examen microscopique, amplification en chaîne par polymérase (PCR), histopathologie et mise en culture), la PCR est la plus rapide et la plus courament employée. D’autres méthodes rapides, comme l’utilisation de la chromatographie sur couche mince par fluorescence pour détecter la mycolactone dans les lésions des cas suspects d’ulcère de Buruli, sont actuellement à l’étude dans quatre pays d’Afrique. Des travaux de recherche sont en cours pour mettre au
point des tests utilisables sur le lieu des soins. Le traitement de l’ulcère de Buruli consiste à administrer une association d’antibiotiques (rifampicine et clarithromycine) pendant 8 semaines. Des traitements complémentaires, comme le soin des plaies, les greffes cutanées et la prévention des incapacités, sont nécessaires dans certains cas pour parvenir à une guérison complète.
La cible fixée par l’Organisation mondiale de la Santé (OMS) exigée des pays pour assurer la lutte contre l’ulcère de Buruli est la confirmation d’au moins 70 % des cas par PCR pour chaque pays. Tous les pays d’endémie disposent d’au moins un établissement doté des moyens nécessaires pour effectuer les tests de PCR pour la confirmation des cas. Cependant, la plupart des pays de la Région africaine n’ont pas réussi à atteindre la cible fixée. Un déclin du taux de confirmation a même été observé.
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Au total, 18 laboratoires de 13 pays ont participé aux quatre cycles d'AQE : 10 laboratoires de huit pays africains endémiques, dont quatre ont participé aux quatre cycles et trois à trois cycles. Les résultats globaux ont montré que la performance médiane de ces laboratoires s'est amélioré...e au cours des quatre cycles. Cependant, la proportion de laboratoires rapportant des cas faussement positifs reste élevée et indique un problème de spécificité probablement dû à une contamination. La proportion de laboratoires rapportant à la fois des résultats faussement positifs et faussement négatifs soulève la question de la qualité des données rapportées par l'OMS en Afrique ainsi que des résultats des études menées dans ces différents laboratoires dans divers pays.
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The meeting was held from 26 to 27 March 2018 to review and discuss the following topics:
Advances and challenges in the use of fTLC, and new approaches to detecting mycolactone using monoclonal antibodies (mAbs).
The status of development of rapid diagnostic tests (RDTs) targeting the M...UL_3720 protein.
The role of PCR as a reference test, and hurdles in providing a confirmatory diagnosis and in establishing a quality assurance programme.
New molecular tools with potential for implementation at a level lower than in the national or regional reference laboratory, such as loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA).
The need to harmonize and standardize methods for collection and preparation of specimens, so samples can be referred for diagnosis and stored for evaluation of new diagnostic tests in optimal conditions.
Barriers to accessing early diagnosis and treatment, including coordination at the programme level, and lack of adequate diagnostic tools.
Defining target product profiles (TPPs) to guide the development of new diagnostic tools that can be applied at different levels of the health system. Participants agreed that two TPPs would be developed to address the current gaps: (i) a rapid test for BU diagnosis at the primary health-care level; and (ii) a test for diagnosis of BU that can also assist in treatment monitoring and differential diagnosis at the district hospital or reference centre.
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Parasites & Vectors volume 11, Article number: 264 (2018)
Dengue creates a staggering epidemiological and economic burden for endemic countries. Without a specific therapy and with a commercial vaccine that presents some problems relative to its full effectiveness, initiatives to improve vector... control strategies, early disease diagnostics and the development of vaccines and antiviral drugs are priorities. In this study, we present the probable origins of dengue in America and the trajectories of its spread. Overall, dengue diagnostics are costly, making the monitoring of dengue epidemiology more difficult and affecting physicians’ therapeutic decisions regarding dengue patients, especially in developing countries. This review also highlights some recent and important findings regarding dengue in Brazil and the Americas. We also summarize the existing DENV polymerase chain reaction (PCR) diagnostic tests to provide an improved reference since these tests are useful and accurate at discriminating DENV from other flaviviruses that co-circulate in the Americas. Additionally, these DENV PCR assays ensure virus serotyping, enabling epidemiologic monitoring.
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J Clin Med . 2020 May 18;9(5):1517. doi: 10.3390/jcm9051517.
Chagas disease (CD) is a major burden in Latin America, expanding also to non-endemic countries. A gold standard to detect the CD causing pathogen Trypanosoma cruzi is currently not available. Existing real time polymerase chain reaction...s (RT-PCRs) lack sensitivity and/or specificity. We present a new, highly specific RT-PCR for the diagnosis and monitoring of CD.
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For the molecular diagnosis of Chagas disease by real-time PCR (polymerase chain reaction), optimization of diagnostic accuracy is desirable. The detection limit of real-time PCR assays for the diagnosis of Trypanosoma cruzi in human serum is affected by various influences including the choice of th...e nucleic acid extraction assay. In this study, three nucleic acid extraction assays were compared regarding their influence on the sensitivity of a T. cruzi-specific real-time PCR with 62 reference sera containing T. cruzi target DNA (deoxyribonucleotide acid). More than 95% of the positive sera were correctly identified after all three nucleic acid extraction strategies with a detection rate ranging from 96.8% (60/62) for the worst assay to 100% (62/62) for the best one. A matched pairs analysis for the comparison of the cycle threshold (Ct) values obtained with the 59 reference samples with positive real-time PCR results after all three nucleic acid extraction schemes indicated differences in a range of about 3 Ct steps. Summarized, all three compared nucleic acid extraction schemes were basically suitable for T. cruzi-specific PCR from serum with some minor differences. However, in the case of low quantities of circulating parasite DNA in the serum of a patient with Chagas disease, even minor effects can make a difference in the individual diagnosis.
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