scholarly journals Performance Evaluation of Standard Health System Microscopy and Rapid Diagnostic Test for the Focused Screening and Treatment of Malaria in South-eastern Tanzania

2021 ◽  
Author(s):  
lin kangming ◽  
Duoquan Wang ◽  
Prosper Chaki ◽  
Michael Mihayo ◽  
Fei Luo ◽  
...  
Keyword(s):  
Health System ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Diagnostic Performance ◽  
False Negative ◽  
Rapid Diagnostic Tests ◽  
Malaria Burden ◽  
South Eastern ◽  
Local Standard ◽  
Sensitivity Specificity

Abstract Background: The Focused screening and treatment (FSAT) has been identified as one of the key approaches for reducing the malaria burden in Tanzania. However, the diagnostic performance of the local standard health system microscopy and rapid diagnostic tests (RDT) for the malaria infections is yet to be established. Thus, we aimed to evaluate the performance of the local standard health system microscopy and RDTs in comparison to that of the gold standard modality through the re-examination of blood slide microscopy findings. Methods: We used the paired RDTs and standard health system microscopy results from the participants screened in the FSAT during 2015–2016. With the gold standard modality as reference, the results of local standard health system microscopy and RDTs were evaluated according to their sensitivity, specificity and reliability.Results: A total of 1,497 paired standard health system microscopy and RDTs results were analysed. Of these, 679 (45.4%) samples and 818 (54.6%) samples were from the high transmission areas (HTA) and low transmission areas (LTA) in the Rufiji District of south eastern Tanzania, respectively. With the gold standard as the reference, the sensitivity of RDTs were higher than those of standard health system microscopy (87.10% vs 76.88%) and (86.99% vs 65.04%) in the HTA and LTA, respectively. Further, the false-negative rates of RDTs were lower than those of standard microscopy in both HTA (12.90% vs 13.01%) and LTA (23.12% vs 34.96%). Conclusions: RDTs have better performance than the standard health system microscopy in terms of sensitivity and specificity for FSAT in study areas in Tanzania.

The diagnostic performance of rapid diagnostic tests and microscopy for malaria diagnosis in eastern Sudan using a nested polymerase chain reaction assay as a reference standard

2019 ◽  
Vol 113 (11) ◽  
pp. 701-705 ◽  
Author(s):  
Zakya A Abdalla ◽  
NourElhouda A Rahma ◽  
Elhashimi E Hassan ◽  
Tajeldin M Abdallah ◽  
Hadeel E Hamad ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Diagnostic Performance ◽  
Malaria Diagnosis ◽  
Rapid Diagnostic Tests ◽  
Chain Reaction ◽  
Nested Polymerase Chain Reaction ◽  
Polymerase Chain ◽  
Eastern Sudan

Abstract Background Accurate diagnosis of malaria infection is essential for successful control and management of the disease. Both microscopy and rapid diagnostic tests (RDTs) are recommended for malaria diagnosis, however, RDTs are more commonly used. The aim of the current study was to assess the performance of microscopy and RDTs in the diagnosis of Plasmodium falciparum infection using a nested polymerase chain reaction (PCR) assay as the gold standard. Methods A cross-sectional study was carried out in Kassala Hospital, eastern Sudan. A total of 341 febrile participants of all ages were recruited. Blood specimens were collected and malaria testing was performed using an RDT (SD Bioline Malaria Ag Pf), microscopy and nested PCR. The sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) of microscopy and the RDT were investigated. Results The prevalence of P. falciparum malaria infections in this study was 22.9%, 24.3% and 26.7% by PCR, microscopy and RDT, respectively. Compared with microscopy, the RDT had slightly higher sensitivity (80.7% vs 74.3%; p=0.442), equivalent specificity (89.3% vs 90.4%), a similar PPV (69.2% vs 69.8%) and a higher NPV (94.0% vs 92.2%). Conclusions The diagnostic performance of the RDT was better than that of microscopy in the diagnosis of P. falciparum malaria when nested PCR was used as the gold standard.

scholarly journals Comparison of 2D Fat Suppressed Proton Density (FS-PD) and 3D (WATS-c) MRI pulse sequences in evaluation of chondromalacia patellae

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Ahmed Ibrahim Tawfik ◽  
Wael Hamza Kamr ◽  
Saher Ebrahim Taman
Keyword(s):  
Diagnostic Performance ◽  
False Negative ◽  
Pulse Sequences ◽  
Proton Density ◽  
Grading System ◽  
Reference Standard ◽  
Mr Images ◽  
Arthroscopic Findings ◽  
Chondromalacia Patella ◽  
Sensitivity Specificity

Abstract Background Comparing the diagnostic performance of widely used 2D FSE technique (fat-suppressed proton density; FS-PD) and the 3D technique (water-selective cartilage scan; WATS-c) in evaluation of the chondromalacia patella by using arthroscopy as reference standard Results Seventy-five adult patients were enrolled in this study. They underwent MRI examinations then arthroscopy done in 2–4 days after it. MRI was done using 2D (FS-PD) and 3D (WATS-c) sequences and MR images were compared by two radiologists separately, then grading of the cartilage lesions was performed according to modified Noyes grading system and comparison between grade 0–1, 2, and 3 lesions was done using arthroscopic findings as a reference. A false-negative result is considered if there was undergrading of chondromalacia and false-positive result if chondromalacia was overgraded. Each sequence sensitivity, specificity, and accuracy was calculated by both readers. For reader 1, the sensitivity is 69% for WATS-c and 80% for FS-PD and the accuracy is 90% for WATS-c and 92% for FS-PD and for reader 2, the sensitivity is 56% for WATS-c and 84% for FS-PD and the accuracy is 88% for WATS-c and 94% for FS-PD. Conclusion 2D FS-PD images showed better diagnostic performance than 3D WATS-c images for evaluating chondromalacia patella.

scholarly journals Evaluation of two new rapid diagnostic tests (RDTs) for the diagnosis of malaria

2013 ◽  
Vol 5 (2) ◽  
pp. 11-15 ◽  
Author(s):  
Fahmida Jahan ◽  
Rubayet Elahi ◽  
Md. Khaja Mohiuddin ◽  
Md. Gulam Musawwir Khan ◽  
Mohammad Shafiul Alam ◽  
...  
Keyword(s):  
Predictive Value ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Accurate Diagnosis ◽  
The Other ◽  
Antibody Detection ◽  
Resource Limited Settings ◽  
Malaria Rdts ◽  
Resource Limited

Rapid diagnostic tests (RDTs) address the need for accurate diagnosis of malaria, particularly in resource limited settings. In this study, two malaria RDTs were compared with gold standard microscopy: On Site Pf/Pv test detecting Plasmodium falciparum-specific histidine rich protein-2 (Pf HR P2) and P. vivax-specific parasitic lactate dehydrogenase (pLDH) antigens; and SD Bioline anti-Pf/Pv test detecting anti-HR P2 and anti-pL DH antibodies for the diagnosis of P. falciparum and P. vivax infections, respectively. For OnSite test, the overall sensitivity was found 96.2% , specificity 98.2% , positive predictive value (PPV ) 98.2% , negative predictive value (NPV ) 96.4% and agreement with microscopy was found to be 0.94. On the other hand SD Bioline test, the overall sensitivity was 75.4%, specificity 83.7%, PPV 84.3% , NPV 74.5% and agreement with microscopy was 0.59. These data revealed that the R DT based on antigen detection (Onsite test) was more reliable than that based on the antibody detection (SD Bioline test).DOI: http://dx.doi.org/10.3329/bjmm.v5i2.16931 Bangladesh J Med Microbiol 2011; 05 (02): 11-15

scholarly journals PO 8271 PFHRP2 GENE DELETIONS IN PLASMODIUM FALCIPARUM AND SCHISTOSOMA MANSONI CO-INFECTIONS: AN EMERGING CHALLENGE FOR MALARIA RAPID DIAGNOSTIC TESTS

2019 ◽  
Vol 4 (Suppl 3) ◽  
pp. A25.2-A25
Author(s):  
Hilda Echelibe ◽  
Masumbe Netongo Palmer ◽  
Nji Akindeh ◽  
Wilfred Mbacham
Keyword(s):  
Plasmodium Falciparum ◽  
Schistosoma Mansoni ◽  
Diagnostic Tests ◽  
False Negative ◽  
Rapid Diagnostic Tests ◽  
Sub Saharan Africa ◽  
P Value ◽  
Gene Deletions ◽  
Malaria Rdts ◽  
Malaria Rapid Diagnostic Tests

BackgroundMalaria and schistosomiasis are infections that have a great impact in sub-Saharan Africa based on their high morbidity and mortality rates. We suggest the possibility that the microenvironment created from interactions between the parasites involved generates a pressure on the malaria parasite which could in turn favour the parasite’s adaptation or escape through Pfhrp2 gene deletions. Thus, this study aimed at determining the association between the co-infection with both parasites and false-negative PfHRP2-based malaria rapid diagnostic tests which occur because of these deletions.MethodsThis pilot study was conducted in a total of 149 children aged 7–17 years living in Yorro, located in the Mbam-Inoubou division of the Center region of Cameroon. We collected fresh stool samples from each participant to identify Schistosoma mansoni (Sm) eggs by Kato Katz method and blood samples to identify the ring stages of Plasmodium falciparum (Pf) by thick smear. Malaria rapid diagnostic test and Pfhrp2 gene polymerase chain reaction were performed. The association between the co-infection with Sm/Pf and the false-negative malaria RDTs was determined by the Fisher’s exact test. A p value<0.05 was considered statistically significant.ResultsOur results showed that samples were singly infected with Sm, Pf, co-infected (Sm/Pf) and negative for both infections at frequencies of 12%, 43%, 30.2% and 14.8% respectively. False-negative PfHRP2-based RDTs were observed in 4.7% of the participants. A higher frequency (5/7) of the cases with false-negative malaria RDTs were co-infected with Sm/Pf. A p value of 0.027 showed statistical significance in the association of Sm/Pf co-infection and false-negative PfHRP2-based RDTs.ConclusionA significant association of Plasmodium falciparum and Schistosoma mansoni co-infection with false-negative PfHRP2-based RDTs supports the case for a plausible implication of Pfhrp2 gene deletions, with consequences for malaria rapid diagnostic testing.

Diagnostic Tests in Occupational Therapy: A Model for Evaluation

1987 ◽  
Vol 7 (2) ◽  
pp. 111-122 ◽  
Author(s):  
Mary C. Law ◽  
Helene J. Polatajko
Keyword(s):  
Occupational Therapy ◽  
Predictive Value ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Southern California ◽  
Sensitivity Specificity

This article describes a model for the evaluation of diagnostic tests used in occupational therapy. In this model, new diagnostic tests are compared to valid tests (“gold standard”), and their sensitivity, specificity, predictive value, and agreement are calculated. The use of this method is illustrated with data from the Southern California Postrotary Nystagmus Test and the Stille-Werner Rotation Chair.

scholarly journals Prozone-like phenomenon in travellers with fatal malaria: report of two cases

2015 ◽  
Vol 9 (03) ◽  
pp. 321-324 ◽  
Author(s):  
Lurdes Santos ◽  
Nuno Rocha Pereira ◽  
Paulo Andrade ◽  
Paulo Figueiredo Dias ◽  
Carlos Lima Alves ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
False Negative ◽  
Specific Antigen ◽  
Malaria Diagnosis ◽  
High Sensitivity ◽  
Rapid Diagnostic Tests ◽  
Microscopy Observation ◽  
Negative Results ◽  
False Negative Results ◽  
Potential Benefits

Malaria diagnosis remains a concern in non-endemic countries, with rapid diagnosis being crucial to improve patients’ outcome. Rapid diagnostic tests have high sensitivity but they also have flaws and false-negative results that might jeopardize malaria diagnosis. Some false-negative results might relate to a prozone-like effect. The authors describe two patients with false-negative rapid diagnostic tests in which a prozone-like effect might have been involved. The authors highlight that these tests should not be used without accompanying light microscopy observation of blood films and discuss potential benefits of using rapid diagnostic tests with more than one specific antigen for Plasmodium falciparum.

scholarly journals Evaluation of Sensitivity, Specificity, and Cost-Effectiveness of Paper-Based Microfluidics for DNA Diagnostics of Malaria versus Nucleic Acid Test (NAT) Versus Rapid Diagnostic Tests (RDT) in Resource-Limited Settings: A Protocol

2021 ◽  
pp. 160-168
Author(s):  
Usha Adiga ◽  
Tirthal Rai
Keyword(s):  
Statistical Analysis ◽  
Cost Effectiveness ◽  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Cost Effectiveness Ratio ◽  
Dna Diagnostics ◽  
Effectiveness Analysis ◽  
Paper Based Microfluidics ◽  
Sensitivity Specificity

Objective: The objective of the study is to compare three techniques, routinely used rapid diagnostic tests (lateral flow immune chromatography) versus nucleic acid amplification test (NAT)  versus Paper-based microfluidics for DNA diagnostics of Malaria, in terms of their sensitivity and specificity as diagnostic tests in detecting malarial infection among febrile illnesses, suspected of malaria, as well as to compare their cost-effectiveness. Methodology: Three seventy febrile cases suspected of malaria with negative results with RDT will be screened by real-time PCR and DNA microfluidics techniques, sensitivity and specificity of these as screening tests will be compared. The number of extra positive cases detected by NAT gives us the yield. Cost-effectiveness analysis will be done by calculating the incremental cost-effectiveness ratio (ICER) and average cost-effectiveness ratio (ACER) for the tests. Statistical Analysis: Statistical analysis will be done using SPSS version 21. Sensitivity, specificity, Positive predictive values will be computed. Comparison of sensitivity and specificity of NAT, a paper microfluidic technique for DNA diagnostics and RDT will be carried out using McNemar’s test. Receiver operating curves will be generated separately to assess the utility of the NAT. Conclusion: The Implications of this study from the patient's perspective would mean early diagnosis which forms the tenet of control of the disease by increasing the yield. Early diagnosis at the community level would translate into the application of efficient prevention mechanisms to spread the infection. The cost-effectiveness analysis would provide a scientific basis for the adoption of the best test for the diagnosis, given the economic feasibility of the study.

scholarly journals Deletions of pfhrp2 and pfhrp3 genes were uncommon in rapid diagnostic test-negative Plasmodium falciparum isolates from Uganda

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Sam L. Nsobya ◽  
Andrew Walakira ◽  
Elizabeth Namirembe ◽  
Moses Kiggundu ◽  
Joaniter I. Nankabirwa ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Protein Expression ◽  
Diagnostic Tests ◽  
False Negative ◽  
Pcr Amplification ◽  
Rapid Diagnostic Tests ◽  
False Negatives ◽  
Cross Sectional ◽  
True Prevalence ◽  
Blood Smears

Abstract Background Rapid diagnostic tests (RDTs) play a key role in malaria case management. The most widely used RDT identifies Plasmodium falciparum based on immunochromatographic recognition of P. falciparum histidine-rich protein 2 (PfHRP2). Deletion of the paralogous pfhrp2 and pfhrp3 genes leads to false-negative PfHRP2-based RDTs, and has been reported in P. falciparum infections from South America and Africa. However, identification of pfhrp2/pfhrp3 deletions has usually been based only on failure to amplify these genes using PCR, without confirmation based on PfHRP2 protein expression, and understanding of the true prevalence of deletions is incomplete. Methods Deletions of pfhrp2/pfhrp3 in blood samples were investigated from cross-sectional surveys in 2012-13 in three regions of varied malaria transmission intensity in Uganda. Samples with positive Giemsa-stained thick blood smears, but negative PfHRP2-based RDTs were evaluated by PCR amplification of conserved subunit ribosomal DNA for Plasmodium species, PCR amplification of pfhrp2 and pfhrp3 genes to identify deletions, and bead-based immunoassays for expression of PfHRP2. Results Of 3516 samples collected in cross-sectional surveys, 1493 (42.5%) had positive blood smears, of which 96 (6.4%) were RDT-negative. Of these 96 RDT-negative samples, P. falciparum DNA was identified by PCR in 56 (58%) and only non-falciparum plasmodial DNA in 40 (42%). In all 56 P. falciparum-positive samples there was a failure to amplify pfhrp2 or pfhrp3: in 25 (45%) pfhrp2 was not amplified, in 39 (70%) pfhrp3 was not amplified, and in 19 (34%) neither gene was amplified. For the 39 P. falciparum-positive, RDT-negative samples available for analysis of protein expression, PfHRP2 was not identified by immunoassay in only four samples (10.3%); these four samples all had failure to amplify both pfhrp2 and pfhrp3 by PCR. Thus, only four of 96 (4.2%) smear-positive, RDT-negative samples had P. falciparum infections with deletion of pfhrp2 and pfhrp3 confirmed by failure to amplify the genes by PCR and lack of expression of PfHRP2 demonstrated by immunoassay. Conclusion False negative RDTs were uncommon. Deletions in pfhrp2 and pfhrp3 explained some of these false negatives, but most false negatives were not due to deletion of the pfhrp2 and pfhrp3 genes.

Sign in / Sign up

Export Citation Format

Share Document