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Malaria Journal Sep 2020Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for... (Review)
Review
Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies. These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.
Topics: Diagnostic Tests, Routine; Humans; Laboratory Proficiency Testing; Malaria; Microscopy; Quality Control; Reproducibility of Results; Sensitivity and Specificity; Staining and Labeling
PubMed: 32887612
DOI: 10.1186/s12936-020-03352-z -
Malaria Journal Mar 2022Progress towards malaria elimination has stagnated, partly because infections persisting at low parasite densities comprise a large reservoir contributing to ongoing...
Diagnostic performance and comparison of ultrasensitive and conventional rapid diagnostic test, thick blood smear and quantitative PCR for detection of low-density Plasmodium falciparum infections during a controlled human malaria infection study in Equatorial Guinea.
BACKGROUND
Progress towards malaria elimination has stagnated, partly because infections persisting at low parasite densities comprise a large reservoir contributing to ongoing malaria transmission and are difficult to detect. This study compared the performance of an ultrasensitive rapid diagnostic test (uRDT) designed to detect low density infections to a conventional RDT (cRDT), expert microscopy using Giemsa-stained thick blood smears (TBS), and quantitative polymerase chain reaction (qPCR) during a controlled human malaria infection (CHMI) study conducted in malaria exposed adults (NCT03590340).
METHODS
Blood samples were collected from healthy Equatoguineans aged 18-35 years beginning on day 8 after CHMI with 3.2 × 10 cryopreserved, infectious Plasmodium falciparum sporozoites (PfSPZ Challenge, strain NF54) administered by direct venous inoculation. qPCR (18s ribosomal DNA), uRDT (Alere™ Malaria Ag P.f.), cRDT [Carestart Malaria Pf/PAN (PfHRP2/pLDH)], and TBS were performed daily until the volunteer became TBS positive and treatment was administered. qPCR was the reference for the presence of Plasmodium falciparum parasites.
RESULTS
279 samples were collected from 24 participants; 123 were positive by qPCR. TBS detected 24/123 (19.5% sensitivity [95% CI 13.1-27.8%]), uRDT 21/123 (17.1% sensitivity [95% CI 11.1-25.1%]), cRDT 10/123 (8.1% sensitivity [95% CI 4.2-14.8%]); all were 100% specific and did not detect any positive samples not detected by qPCR. TBS and uRDT were more sensitive than cRDT (TBS vs. cRDT p = 0.015; uRDT vs. cRDT p = 0.053), detecting parasitaemias as low as 3.7 parasites/µL (p/µL) (TBS and uRDT) compared to 5.6 p/µL (cRDT) based on TBS density measurements. TBS, uRDT and cRDT did not detect any of the 70/123 samples positive by qPCR below 5.86 p/µL, the qPCR density corresponding to 3.7 p/µL by TBS. The median prepatent periods in days (ranges) were 14.5 (10-20), 18.0 (15-28), 18.0 (15-20) and 18.0 (16-24) for qPCR, TBS, uRDT and cRDT, respectively; qPCR detected parasitaemia significantly earlier (3.5 days) than the other tests.
CONCLUSIONS
TBS and uRDT had similar sensitivities, both were more sensitive than cRDT, and neither matched qPCR for detecting low density parasitaemia. uRDT could be considered an alternative to TBS in selected applications, such as CHMI or field diagnosis, where qualitative, dichotomous results for malaria infection might be sufficient.
Topics: Adolescent; Adult; Diagnostic Tests, Routine; Equatorial Guinea; Humans; Malaria; Plasmodium falciparum; Real-Time Polymerase Chain Reaction; Young Adult
PubMed: 35331251
DOI: 10.1186/s12936-022-04103-y -
Revue Scientifique Et Technique... Jun 2021To select, interpret, and assess the fitness-for-purpose of diagnostic tests, we need to compare the likelihoods of test results being true vs. false across both...
To select, interpret, and assess the fitness-for-purpose of diagnostic tests, we need to compare the likelihoods of test results being true vs. false across both infected and non-infected individuals. Diagnostic sensitivity (DSe) and specificity (DSp) report the accuracy of classification in infected and non-infected individuals separately and do not compare these likelihoods directly. Positive and negative predictive values combine these likelihoods, but they also heavily depend on the prevalence in the tested populations and, therefore, cannot be generalised. We propose the adoption of the diagnostic likelihood ratio (LR), which balances the likelihoods of true vs. false results and is population independent. As a relative measure, LR ignores the absolute accuracy of tests, and two tests with different accuracy profiles may have the same LR. This can be easily mitigated by using listed complementary measures of accuracy, including DSe and DSp, or ancillary selection criteria. Overall, LR is a more relevant and universal measure of diagnostic test accuracy, which makes it the logical next-generation measure to adopt. We illustrate the applications and benefits of LR using three assays certified by the World Organisation for Animal Health as serological tests for bovine tuberculosis.
Topics: Animals; Diagnostic Tests, Routine; Predictive Value of Tests; Sensitivity and Specificity; Serologic Tests
PubMed: 34140723
DOI: 10.20506/rst.40.1.3226 -
Journal of Veterinary Science Mar 2020African swine fever (ASF) is a highly contagious disease of domestic pigs and wild boars (WBs). Without a vaccine, early antibody and antigen detection and rapid... (Review)
Review
African swine fever (ASF) is a highly contagious disease of domestic pigs and wild boars (WBs). Without a vaccine, early antibody and antigen detection and rapid diagnosis are crucial for the effective prevention of the disease and the employment of control measures. In Sardinia, where 3 different suid populations coexisted closely for a long time, the disease persists since 1978. The recent ASF eradication plan involves more stringent measures to combat free-ranging pigs and any kind of illegality in the pig industry. However, critical issues such as the low level of hunter cooperation with veterinary services and the time required for ASF detection in the WBs killed during the hunting season still remain. Considering the need to deliver true ASF negative carcasses as early as possible, this study focuses on the evaluation and validation of a duplex pen-side test that simultaneously detects antibodies and antigens specific to ASF virus, to improve molecular diagnosis under field conditions. The main goal was to establish the specificity of the two pen-side tests performed simultaneously and to determine their ability to detect the true ASF negative carcasses among the hunted WBs. Blood and organ samples of the WBs hunted during the 2018/2019 hunting seasons were obtained. A total of 160 animals were tested using the pen-side kit test; samples were collected for virological and serological analyses. A specificity of 98% was observed considering the official laboratory tests as gold standards. The new diagnostic techniques could facilitate faster and cost-effective control of the disease.
Topics: African Swine Fever; African Swine Fever Virus; Animals; Cost-Benefit Analysis; Diagnostic Tests, Routine; Italy; Swine
PubMed: 31940693
DOI: 10.4142/jvs.2020.21.e14 -
Diagnosis (Berlin, Germany) Aug 2021A positive patient experience has been long recognised as a key feature of a high-quality health service, however, often assessment of patient experience excludes...
A positive patient experience has been long recognised as a key feature of a high-quality health service, however, often assessment of patient experience excludes diagnostic care. Experience of diagnostic services and the acceptability of diagnostic tests are often conflated, with lack of clarity about when and how either should be measured. These problems contrast with the growth in the development and marketing of new tests and investigation strategies. Building on the appraisal of current practice, we propose that the experience of diagnostic services and the acceptability of tests should be assessed separately, and describe distinct components of each. Such evaluations will enhance the delivery of patient-centred care, and facilitate patient choice.
Topics: Diagnostic Tests, Routine; Humans; Patient Outcome Assessment; Patient-Centered Care
PubMed: 33544479
DOI: 10.1515/dx-2020-0112 -
The European Respiratory Journal Jan 2020
Topics: Diagnostic Tests, Routine; Humans; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Patient Reported Outcome Measures
PubMed: 31949103
DOI: 10.1183/13993003.02204-2019 -
Reproduction & Fertility Jul 2022Endometriosis is a benign disease that can cause pain and infertility in women. Debate exists over how endometriosis should best be diagnosed. On one hand, endometriosis... (Review)
Review
Endometriosis is a benign disease that can cause pain and infertility in women. Debate exists over how endometriosis should best be diagnosed. On one hand, endometriosis can be diagnosed by directly examining pelvic anatomy via a surgical procedure known as diagnostic laparoscopy. On the other hand, the disease can be diagnosed via non-surgical means such as using medical imaging, the symptoms described by the patient and whether the patient responds to non-surgical therapies such as medication. In this debate article, we argue in favour of diagnostic laparoscopy. We review the safety of the procedure, compare the ability of diagnostic laparoscopy vs medical imaging to detect endometriosis and consider the benefits of formally diagnosing or ruling out the condition.
Topics: Animals; Diagnostic Tests, Routine; Endometriosis; Female; Humans; Laparoscopy; Pelvic Pain; Pelvis; Service Animals
PubMed: 35794928
DOI: 10.1530/RAF-21-0117 -
Clinical Infectious Diseases : An... Jan 2022The emergence and spread of Plasmodium falciparum parasites that lack HRP2/3 proteins and the resulting decreased utility of HRP2-based malaria rapid diagnostic tests...
BACKGROUND
The emergence and spread of Plasmodium falciparum parasites that lack HRP2/3 proteins and the resulting decreased utility of HRP2-based malaria rapid diagnostic tests (RDTs) prompted the World Health Organization and other global health stakeholders to prioritize the discovery of novel diagnostic biomarkers for malaria.
METHODS
To address this pressing need, we adopted a dual, systematic approach by conducting a systematic review of the literature for publications on diagnostic biomarkers for uncomplicated malaria and a systematic in silico analysis of P. falciparum proteomics data for Plasmodium proteins with favorable diagnostic features.
RESULTS
Our complementary analyses led us to 2 novel malaria diagnostic biomarkers compatible for use in an RDT format: glyceraldehyde 3-phosphate dehydrogenase and dihydrofolate reductase-thymidylate synthase.
CONCLUSIONS
Overall, our results pave the way for the development of next-generation malaria RDTs based on new antigens by identifying 2 lead candidates with favorable diagnostic features and partially de-risked product development prospects.
Topics: Antigens, Protozoan; Biomarkers; Diagnostic Tests, Routine; Humans; Malaria; Malaria, Falciparum; Plasmodium falciparum; Protozoan Proteins; Sensitivity and Specificity
PubMed: 34718455
DOI: 10.1093/cid/ciab251 -
Critical Care (London, England) Nov 2019
Topics: Anti-Bacterial Agents; Diagnostic Tests, Routine; Humans; Infections; Practice Patterns, Physicians'; Sepsis
PubMed: 31783896
DOI: 10.1186/s13054-019-2675-3 -
Journal of Clinical Microbiology Jul 2020In this commentary, we provide a broad overview of how the rapidly evolving coronavirus disease 2019 (COVID-19) diagnostic landscape has impacted clinical care during... (Review)
Review
In this commentary, we provide a broad overview of how the rapidly evolving coronavirus disease 2019 (COVID-19) diagnostic landscape has impacted clinical care during the COVID-19 pandemic. We review aspects of both molecular and serologic testing and discuss the logistical challenges faced with each. We also highlight the progress that has been made in the development and implementation of these assays as well as the need for ongoing improvement in diagnostic testing capabilities.
Topics: Betacoronavirus; COVID-19; COVID-19 Testing; Clinical Laboratory Techniques; Coronavirus Infections; Diagnostic Tests, Routine; Humans; Pandemics; Pneumonia, Viral; SARS-CoV-2
PubMed: 32703894
DOI: 10.1128/JCM.01287-20