scholarly journals Optimization of Case Definitions for Sensitivity as a Preventive Strategy—A Modelling Exemplified with Rapid Diagnostic Test-Based Prevention of Sexual HIV Transmission

Diagnostics ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2079
Author(s):  
Andreas Hahn ◽  
Hagen Frickmann ◽  
Ulrike Loderstädt
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Hiv Transmission ◽  
Clinical Symptoms ◽  
High Sensitivity ◽  
Clinical State ◽  
Preventive Strategy ◽  
Case Definitions ◽  
Predictive Values ◽  
High Level

In clinical studies, case definitions are usually designed to optimally match the desired clinical state, because lacking specificity is associated with a risk of bias regarding the study outcome. In preventive medicine, however, high sensitivity is sometimes considered as more critical in order not to overlook infectious individuals, because the latter may be associated with ongoing spread of a transmittable disease. Accordingly, this work was focused on a theoretical model on how the sensitivity of case definitions can be optimized by adding clinical symptoms to diagnostic results for preventive purposes, if the associated reduction in specificity is considered as acceptable. The model was exemplified with an analysis on whether and in how far exposure risk can be reduced by the inclusion of observable symptoms during seroconversion syndrome in case of rapid diagnostic test-based prevention of sexual HIV transmission. The approach provided a high level of safety (negative predictive values close to 1) for the price of a considerably number of false positives (positive predictive values < 0.01 for some subpopulations). When applying such a sensitivity-optimized screening as a “diagnostics as prevention” strategy, the advantages of excellent negative predictive values need to be cautiously balanced against potential undesirable consequences of low positive predictive values.

scholarly journals Evaluation of a Rapid Diagnostic Test Currently Being Used in the Management of Malaria in Patients of the Hia/Chu-Parakou and the Boko Zone Hospital in Northern Benin

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Tokponnon F ◽  
◽  
Osse R ◽  
Houessou C ◽  
Akogbeto M ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Probabilistic Method ◽  
Health Centers ◽  
Patient Identification ◽  
Cross Sectional ◽  
Predictive Values ◽  
Parasitological Diagnosis ◽  
Sensitivity Specificity ◽  
Adequate Management

Parasitological diagnosis is a fundamental element in the adequate management of the disease. In the last decade, there has been a resurgence of interest in the development of malaria Rapid Diagnostic Test (RDT) kits. This is the case with SD Bioline Malaria Ag Pf, which searches for HRP2 antigen by immunochromatography. The objective of this study is to compare the results of RDT SD Bioline Malaria Ag Pf in use with the results of Thick Gout (TG) in the biological diagnosis of malaria. This was a cross-sectional, descriptive and evaluative study carried out at the Hôpital d’Instruction des Armées-Center Hospitalier et Universitaire de Parakou and at the Boko zone hospital from April 20 to July 30, 2015. Patient identification, we used the non-probabilistic method and the convenience choice technique. The study involved 503 patients. The results of this study showed a good performance of the RDT SD Bioline Malaria Ag Pf. Among the 503 patients, 199 or 39.6% were positive for the RDT against 180 or 35.8% positive for the Thick Gout (TG). Sensitivity, specificity, positive and negative predictive values of the test compared to the thick film were respectively (91.7%, 89.5%, 82.9, 95) and the Kappa coefficient of 0.88 testifies a good match. False positive cases are noted in patients on treatment and even after recovery due to the persistence of the HRP2 antigen in the blood. However, it constitutes an interesting alternative to the management of malaria. At the end of this study, we suggest continuing the use of RDTs in health centers where microscopy is absent and/or reinforcing microscopy, and to strengthen staff training in the management of malaria cases.

scholarly journals Performance evaluation of the Simtomax® CoronaCheck rapid diagnostic test

2020 ◽  
Author(s):  
P. J. Ducrest ◽  
A. Freymond ◽  
J.-M. Segura
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Diagnostic Performance ◽  
High Sensitivity ◽  
High Specificity ◽  
Negative Control ◽  
List Type ◽  
Plasma Samples ◽  
Rt Pcr ◽  
Two Samples

AbstractThe aim of this study was to evaluate the diagnostic performance of Simtomax® CoronaCheck, a serology rapid diagnostic test (RDT) for the detection of IgG and IgM against SARS-CoV-2. 48 plasma samples positive for SARS-CoV-2 based on RT-PCR and 98 negative control samples were studied. Diagnostic performance of the IgG/IgM RDT was assessed against RT-PCR and the electro-chemiluminescence immunoassay (ECLIA) Elecsys® Anti-SARS-CoV-2 total Ig. Overall, the RDT sensitivity was 92% (95% confidence interval [95%CI]: 79-97), specificity 97% (95% CI: 91-99%), PPV 94% (95% CI: 81-98) and the NPV 96% (95% CI: 89-99). When considering only samples collected ≥ 15 days post-symptoms (DPS), the sensitivity increased to 98% (95%CI: 86-100) and the specificity was 97% (95% CI: 91-99%). Two samples with 180 DPS were still positive for IgG. Globally, this IgG/IgM RDT displayed a high diagnostic accuracy for SARS-CoV-2 IgG/IgM detection in plasma samples in high COVID-19 prevalence settings. It could be effectively used, in absence of facilities for routine diagnostic serology, for samples with a DPS between 15 and 180 days.Highlights–The rapid diagnostic test Simtomax CoronaCheck displays a high sensitivity of 98% and a high specificity of 97% for SARS-CoV-2 IgG/IgM detection in plasma samples after 15 days post-symptoms.–The rapid diagnostic test Simtomax CoronaCheck can detect SARS-CoV-2 antibodies in plasma up to 180 days after symptom onset.–The rapid diagnostic test Simtomax CoronaCheck could be effectively used as an alternative to serological analysis using laboratory facilities.

MACE for the Diagnosis of Dementia and MCI: 3-Year Pragmatic Diagnostic Test Accuracy Study

2018 ◽  
Vol 45 (5-6) ◽  
pp. 300-307 ◽  
Author(s):  
John C. Williamson ◽  
Andrew J. Larner
Keyword(s):  
Diagnostic Test ◽  
Cognitive Disorders ◽  
High Sensitivity ◽  
Diagnostic Test Accuracy ◽  
Test Accuracy ◽  
Cognitive Screening ◽  
Predictive Values ◽  
Diagnosis Of Dementia ◽  
Accuracy Study ◽  
Secondary Care Setting

Background/Aims: The Mini-Addenbrooke’s Cognitive Examination (MACE) is a relatively new short cognitive screening instrument for the detection of patients with dementia and mild cognitive impairment (MCI). Few studies of the MACE have been reported hitherto. The aim of this study was to undertake a pragmatic diagnostic test accuracy study of MACE in a large cohort of patients seen in a dedicated cognitive disorders clinic. Methods: MACE was administered to consecutive patients referred to a neurology-led Cognitive Function Clinic over the course of 3 years to assess its performance for the diagnosis of dementia and MCI using various test metrics. Results: In a cohort of 599 patients, the prevalence of dementia and MCI by criterion diagnosis was 0.17 and 0.29, respectively. MACE had a high sensitivity (> 0.9) and negative predictive values (> 0.8) with large effect sizes (Cohen’s d > 1) for the diagnosis of both dementia and MCI but a low specificity (< 0.5) and positive predictive values (≤0.5). Conclusion: MACE is an acceptable test for the assessment of cognitive complaints in a secondary care setting with good metrics for identifying cases of both dementia and MCI.

scholarly journals Diagnostic Accuracy of Clinical Symptoms and Rapid Diagnostic Test in Group A Streptococcal Perianal Infections in Children

2014 ◽  
Vol 60 (2) ◽  
pp. 267-270 ◽  
Author(s):  
R. Cohen ◽  
C. Levy ◽  
S. Bonacorsi ◽  
A. Wollner ◽  
M. Koskas ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Clinical Symptoms ◽  
Group A

scholarly journals Laboratory and Field Evaluation of the Crystal VC-O1 Cholera Rapid Diagnostic Test

2021 ◽  
Author(s):  
Amanda K. Debes ◽  
Kelsey N. Murt ◽  
Ethyl Waswa ◽  
Gerald Githinji ◽  
Mama Umuro ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
High Performance ◽  
Performance Metrics ◽  
Diarrheal Disease ◽  
Low Cost ◽  
Field Evaluation ◽  
Outbreak Detection ◽  
Case Definitions ◽  
Dipstick Test

Cholera is a severe acute, highly transmissible diarrheal disease which affects many low- and middle-income countries. Outbreaks of cholera are confirmed using microbiological culture, and additional cases during the outbreak are generally identified based on clinical case definitions, rather than laboratory confirmation. Many low-resource areas where cholera occurs lack the capacity to perform culture in an expeditious manner. A simple, reliable, and low-cost rapid diagnostic test (RDT) would improve identification of cases allowing rapid response to outbreaks. Several commercial RDTs are available for cholera testing with two lines to detect either serotypes O1 and O139; however, issues with sensitivity and specificity have not been optimal with these bivalent tests. Here, we report an evaluation of a new commercially available cholera dipstick test which detects only serotype O1. In both laboratory and field studies in Kenya, we demonstrate high sensitivity (97.5%), specificity (100%), and positive predictive value (100%) of this new RDT targeting only serogroup O1. This is the first field evaluation for the new Crystal VC-O1 RDT; however, with these high-performance metrics, this RDT could significantly improve cholera outbreak detection and improve surveillance for better understanding of cholera disease burden.

scholarly journals Diagnostic Performance between Histidine-Rich Protein 2 (HRP-2), a Rapid Malaria Diagnostic Test and Microscopic-Based Staining Techniques for Diagnosis of Malaria

2020 ◽  
Vol 2020 ◽  
pp. 1-6 ◽  
Author(s):  
Jean Baptiste Niyibizi ◽  
Emmanuel Kamana Gatera
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Health Centre ◽  
Malaria Diagnosis ◽  
High Specificity ◽  
Cross Sectional Study ◽  
Diagnostic Challenge ◽  
Cross Sectional ◽  
Predictive Values ◽  
Study Participants

Malaria presents a diagnostic challenge in most tropical countries such as Rwanda. Microscopy remains the gold standard for diagnosing malaria, but it is labor intensive and depends upon the skill of the examiner. Malaria rapid diagnostic tests (RDTs) have been developed as an easy, convenient alternative to microscopy. This cross-sectional study was conducted at Rukara Health Center which is located in Eastern Province, Kayonza district, Rwanda. One hundred and fifty suspected cases of malaria, who attended Rukara Health Centre, during the period, from 21st June to 30th July 2018, were included in this study. HRP-2 RDTs (CareStart™ Malaria HRP-2 (Access Bio, Inc., Somerset, New Jersey, USA)), for malaria were performed. Thick smears were prepared and Giemsa-stained as recommended; then slides were observed under microscopy and reported quantitatively; RDTs were reported qualitatively (positive or negative). Both RDTs and thick smear results were recorded on data collection sheet. This study included a total of 150 study participants, 87 (58%) females and 63 (42%) males. The patients included in the study did not receive any antimalarial drug. The mean age of the study participants was 31.6 ± 12.4 with the majority of participants being between 25 and 44 years and the minority being above 65 years. The sensitivity of RDT (HRP-2) was calculated and found to be 95.0%, whereas the sensitivity of Giemsa microscopy was 100%. The specificity of RDT (HRP-2) was calculated and found to be 59.2%, whereas the specificity of Giemsa microscopy was 100%. Negative and positive predictive values of RDT are 85.4% and 82.7%, respectively. Negative and positive predictive values of Giemsa microscopy were both 100%. According to the results of the current study, the sensitivity, specificity, and both positive and negative predictive values of Giemsa microscopy are higher than those of histidine-rich protein 2-based rapid diagnostic test for malaria. The results obtained in histidine-rich protein 2-based rapid diagnostic test for malaria parasites should be confirmed with tests with high specificity. Further studies should determine the most appropriate type of rapid diagnostic test of malaria diagnosis to be used in combination with Giemsa microscopy. In addition, sensitivity and specificity of RDT (HRP-2) and Giemsa microscopy should be assessed against molecular biology techniques.

scholarly journals Accuracy of SD Malaria Ag P.f/Pan® as a rapid diagnostic test in French Amazonia

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jean Marc Pujo ◽  
Stéphanie Houcke ◽  
Sarah Lemmonier ◽  
Patrick Portecop ◽  
Alexis Frémery ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Rapid Test ◽  
Malaria Diagnosis ◽  
Blood Film ◽  
Test Results ◽  
Predictive Values ◽  
Imported Cases ◽  
Remote Healthcare

Abstract Background French Guiana (FG) is a French overseas territory where malaria is endemic. The current incidence rate is 0.74‰ inhabitants, and Plasmodium vivax is widely predominating even though Plasmodium falciparum is still present due to imported cases mainly from Africa. In FG, rapid diagnostic test (SD Malaria Ag P.f/Pan®) is based on the detection of pan-pLDH, PfHRP2, and PfHRP3 antigens, while in South America, the share of deletion of PfHRP2 gene is significantly increasing. Accordingly, the study questions the reliability of RDTs in the Amazonian context. Methods The study is retrospective. It is conducted over 4 years and analysed 12,880 rapid diagnostic tests (RDTs) compared to concomitant Blood Film Tests (BFTs) sampled for malaria diagnosis. Results The global assessment of the accuracy of SD Malaria Ag P.f/Pan® in the diagnostic of malaria shows both Positive and Negative Predictive Values (PPV and NPV) higher than 95%, except for PPV in the diagnosis of malaria to P. falciparum (88%). Overall, the concordance rate between RDT and BFT (positive/positive; negative/negative) was 99.5%. The PPV of the RDT in the follow-up of patients diagnosed with P. falciparum was the lowest during the first 28 days. The PPV of the RDT in the follow-up of patients diagnosed with P. vivax was the lowest during the first 21 days. The global sensitivity of SD Malaria Ag P.f/Pan® test was, on average, 96% (88.2–100) for P. falciparum and 93% (90.6–94.2) for P. vivax. The global specificity was 99.8% (99.5–100) for all included species. Conclusion SD Malaria Ag P.f/Pan® is a reliable rapid test used for the first-line diagnosis in remote healthcare centres. The test results should be interpreted in the light of patient’s recent medical history and the date of arrival to FG.

scholarly journals A COMPARISON OF RAPID DIAGNOSTIC TEST AND MODIFIED ZIEHL-NEELSEN METHOD IN THE DIAGNOSIS OF CRYPTOSPORIDIOSIS.

2021 ◽  
Vol 9 (2) ◽  
pp. 539-542
Author(s):  
Dahal AS ◽  
Daha AS ◽  
Okolo OM ◽  
Onyedibe IK ◽  
Cosmas TN ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Cryptosporidium Parvum ◽  
Severe Illness ◽  
Chain Reaction ◽  
Predictive Values ◽  
Stool Samples ◽  
Polymerase Chain ◽  
Strip Test

Background: Cryptosporidium parvum as a leading cause of persistent diarrhoea in developing countries causes a more severe illness in patients infected with human immunodeficiency virus (HIV). The intermittent shedding of Cryptosporidium parvum oocysts in stool, even in patients with massive diarrhoea, makes diagnosis difficult. This study evaluated the validity of Crypto-Strip test in comparison to the modified Ziehl-Neelsen for the diagnosis of Cryptosporidium infection using polymerase chain reaction (PCR) as gold standard. Methods: This was a hospital based cross-sectional study of 100 HIV positive patients with diarrhoea at a tertiary health facility in Jos, Nigeria. We collected 15mls of stool sample and relevant information from patients who gave informed consent. The oocytes of Cryptosporidium parvum were identified in the stool samples using modified Ziehl-Neelsen stain and Rapid diagnostic test (Crypto-Strip). We also ran all samples using polymerase chain reaction (PCR). Statistical analysis was with statistical package for Social Sciences (SPSS) version 21. Result: Out of the 100 stool samples analysed, 13 (13%) were positive for cryptosporidiosis by PCR. Crypto- Strips recorded 12 (12%) positive with one (1) being false negative as compared to PCR. Conversely, eight (8%) of the 100 samples collected were positive for Cryptosporidium oocysts using modified Ziehl Neelsen (mZN) stain. Out of the eight positives by mZN stain, two were false positive as both tested negative by the PCR. The Crypto-Strip test kit had a sensitivity of 92.3% and a specificity of 100.0% and also positive and negative predictive values of 100.0% and 98.9%, respectively. Whereas, the modified Ziehl Neelsen stain had a sensitivity of 46.2% and a specificity of 97.7% with a positive and negative predictive value of 75.0% and 92.4%, respectively. Conclusion: In this study, we have shown that Crypto-Strip test was a better diagnostic method for the diagnosis of crypto

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