scholarly journals Performance Evaluation of RDT, Light Microscopy, and PET-PCR for Detecting P. Falciparum Malaria Infections in the 2018 Zambia National Malaria Indicator Survey

2021 ◽  
Author(s):  
Mulenga C. Mwenda ◽  
Abebe A. Fola ◽  
Ilinca I. Ciubotariu ◽  
Conceptor Mulube ◽  
Brenda Mambwe ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Light Microscopy ◽  
Transmission Spectrum ◽  
Gold Standard ◽  
Diagnostic Performance ◽  
False Positive Rate ◽  
Test Methods ◽  
High Rate ◽  
Predictive Values ◽  
Malaria Indicator Survey

Abstract BackgroundZambia continues to advance on the path to elimination with significant reductions in malaria morbidity and mortality. Crucial components that have contributed to progress thus far and are necessary for achieving the national malaria elimination goals include properly identifying and treating all malaria cases through accurate diagnosis. This study sought to compare and assess the diagnostic performance of RDTs and LM with PET-PCR as the gold standard using 2018 MIS data across Zambia to better understand diagnostic accuracy metrics and how these vary across a transmission gradient. MethodsCross-sectional samples collected in a nationally representative survey from 7 provinces in Zambia were tested for the presence of malaria parasites by light microscopy (LM), rapid diagnostic test (RDT) and the gold standard PET-PCR. Diagnostic performance was assessed including sensitivity, specificity, negative- and positive-predictive values across a wide malaria transmission spectrum. Diagnostic accuracy metrics were measured, and statistically significant differences were calculated between test methods for different outcome variables. ResultsFrom the individuals included in the MIS, the overall prevalence of P. falciparum malaria was 32.9% by RDT, 19.4% by LM, and 23.2% by PET-PCR. Herein, we compared RDT and LM diagnostic performance against gold standard PET-PCR and found that LM had higher diagnostic accuracy than RDTs (91.3% vs 84.6% respectively) across the transmission spectrum in Zambia. However, we found that the performance of both diagnostics was significantly reduced in low parasitemia samples. Consistent with previous studies, RDT diagnostic accuracy was predominantly affected by a high rate of false positives.ConclusionWhile LM performance is overall superior to RDTs, the additional requirements for its implementation such as high-quality staining, microscopes, and additional manpower, means that its application will remain at the health facility level. In contrast, while RDTs overestimate prevalence as they have a higher false positive rate, their ability to be rapidly deployed makes them an excellent community level tool. Overall, we found that the performance of both diagnostics was acceptable, and their use should be continued.

scholarly journals Performance evaluation of RDT, light microscopy, and PET-PCR for detecting Plasmodium falciparum malaria infections in the 2018 Zambia National Malaria Indicator Survey

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mulenga C. Mwenda ◽  
Abebe A. Fola ◽  
Ilinca I. Ciubotariu ◽  
Conceptor Mulube ◽  
Brenda Mambwe ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Accuracy ◽  
Light Microscopy ◽  
Transmission Spectrum ◽  
Gold Standard ◽  
Diagnostic Performance ◽  
Diagnostic Methods ◽  
High Rate ◽  
Predictive Values ◽  
Malaria Indicator Survey

Abstract Background Zambia continues to advance on the path to elimination with significant reductions in malaria morbidity and mortality. Crucial components that have contributed to progress thus far and are necessary for achieving the national malaria elimination goals include properly identifying and treating all malaria cases through accurate diagnosis. This study sought to compare and assess the diagnostic performance of Rapid Diagnostic Tests (RDT) and Light Microscopy (LM) with photo-induced electron transfer polymerase chain reaction (PET-PCR) as the gold standard using 2018 Malaria Indicator Survey (MIS) data across Zambia to better understand diagnostic accuracy metrics and how these vary across a transmission gradient. Methods Cross-sectional samples collected in a nationally representative survey from 7 provinces in Zambia were tested for the presence of malaria parasites by light microscopy (LM), rapid diagnostic test (RDT) and the gold standard PET-PCR. Diagnostic performance was assessed including sensitivity, specificity, negative- and positive-predictive values across a wide malaria transmission spectrum. Diagnostic accuracy metrics were measured, and statistically significant differences were calculated between test methods for different outcome variables. Results From the individuals included in the MIS, the overall prevalence of Plasmodium falciparum malaria was 32.9% by RDT, 19.4% by LM, and 23.2% by PET-PCR. Herein, RDT and LM diagnostic performance was compared against gold standard PET-PCR with LM displaying a higher diagnostic accuracy than RDTs (91.3% vs. 84.6% respectively) across the transmission spectrum in Zambia. However, the performance of both diagnostics was significantly reduced in low parasitaemia samples. Consistent with previous studies, RDT diagnostic accuracy was predominantly affected by a high rate of false positives. Conclusions RDTs and LM both perform well across a range of transmission intensities within their respective target applications, i.e., in the community, for the former, where ease of use and speed of result is critical, and at the health facility, for the latter, where accuracy is prioritized. However, the performance of both diagnostic methods is adversely affected by low parasitaemia infections. As Zambia moves towards elimination more sensitive tools may be required to identify the last cases.

Accuracy of MRI in the Differential Diagnosis of Wilms Tumor

2021 ◽  
Vol 15 (8) ◽  
pp. 2057-2059
Author(s):  
Maham Ashraf ◽  
Aysha Anjum ◽  
Eisha Tahir ◽  
Amber Goraya ◽  
Rabia Aqeel
Keyword(s):  
Differential Diagnosis ◽  
Diagnostic Accuracy ◽  
Gold Standard ◽  
Wilms Tumor ◽  
Correct Diagnosis ◽  
Renal Tumors ◽  
Common Finding ◽  
Predictive Values ◽  
Female Ratio ◽  
Male Predominance

Background & Objective: Renal tumors are a common finding in diagnostic imaging; these lesions usually are solid or cystic, benign or malignant, and the correct diagnosis may be difficult. The current study aims at to determine the diagnostic accuracy of magnetic resonance imaging for the diagnosis of Wilms tumor taking histopathology as gold standard. Methodology: This cross-sectional study was carried at the Department of Radiology, The Children’s Hospital & Institute of Child Health Lahore over 6 months from March 2019 to September 2019. The study involved 125 children of both genders aged between 2 years to 14 years presenting with a neoplastic mass in the retroperitoneum on ultrasound abdomen during initial workup. These children were assessed on MRI for the diagnosis of Wilms tumor. Later the diagnosis was confirmed on histopathology which was taken as gold standard and the diagnosis of MRI was judged accordingly as true/false and positive/negative. A written informed consent was obtained from every patient. Results: The mean age of the children was 5.8±3.9 years having a male predominance with male to female ratio of 1.8:1. Wilms tumor was suspected in 13 (10.4%) children on MRI. The diagnosis of Wilms tumor was confirmed in 13 (10.4%) children on histopathology. MRI was found to be 76.9% sensitive, 97.3% specific and 95.2% accurate with positive and negative predictive values of 76.9% and 97.3% respectively. Conclusion: In the present study, MRI was found to be 95.2% accurate in the differential diagnosis of Wilms tumor in children presenting with retroperitoneal mass which along with its non-invasive and radiation free nature advocates the preferred use of MRI in the diagnostic evaluation of such children in future oncologic practice. Keywords: Retroperitoneal Tumor, Wilms Tumor, MRI, Diagnostic Accuracy

scholarly journals A Study of the Diagnostic Accuracy of an Existing Multivariable Test to Predict Shoulder Dystocia

2019 ◽  
Vol 09 (03) ◽  
pp. e262-e267
Author(s):  
Henry Alexander Easley ◽  
Todd Michael Beste
Keyword(s):  
Diagnostic Accuracy ◽  
Prediction Model ◽  
Study Design ◽  
False Positive ◽  
False Positive Rate ◽  
Shoulder Dystocia ◽  
The Other ◽  
Predictive Values ◽  
Positive Rate ◽  
Sensitivity Specificity

Objectives To evaluate the diagnostic accuracy of a multivariable prediction model, the Shoulder Screen (Perigen, Inc.), and compare it with the American College of Obstetricians and Gynecologists (ACOG) guidelines to prevent harm from shoulder dystocia. Study Design The model was applied to two groups of 199 patients each who delivered during a 4-year period. One group experienced shoulder dystocia and the other group delivered without shoulder dystocia. The model's accuracy was analyzed. The performance of the model was compared with the ACOG guideline. Results The sensitivity, specificity, positive, and negative predictive values of the model were 23.1, 99.5, 97.9, and 56.4%, respectively. The sensitivity of the ACOG guideline was 10.1%. The false-positive rate of the model was 0.5%. The accuracy of the model was 61.3%. Conclusion A multivariable prediction model can predict shoulder dystocia and is more accurate than ACOG guidelines.

scholarly journals HPV E6/E7 mRNA test for the detection of high grade cervical intraepithelial neoplasia (CIN2+): A systematic review

2019 ◽  
Author(s):  
Awoke Derbie ◽  
Daniel Mekonnen ◽  
Yimtubeznash Woldeamanuel ◽  
Xaveer Van Ostade ◽  
Tamrat Abebe
Keyword(s):  
Systematic Review ◽  
Coming Out ◽  
Gold Standard ◽  
Diagnostic Performance ◽  
Grey Literature ◽  
High Grade ◽  
Operating Characteristics ◽  
Cervical Lesions ◽  
Predictive Values ◽  
Hpv E6

Abstract Background: Genital infection with certain types of Human papillomavirus (HPV) is a major cause of cervical cancer globally. For early detection of premalignant dysplasia, evidences are coming out on the usefulness of HPV E6/E7 mRNA test as a potential tool compared with cytology and HPV DNA testing. Taking into account shortage of compiled data on this field, the aim of this systematic review was to describe the latest diagnostic performance of HPV E6/E7 mRNA testing to detect high grade cervical lesions (CIN2+) where by histology as was taken as a ‘gold standard’. Methods: Articles published in English were systematically searched using key words from PubMed/Medline and SCOPUS. In addition, Google Scholar and the Google database were searched manually for grey literature. Two reviewers independently assessed study eligibility, risk of bias and extracted the data. We performed a descriptive presentation of the performance of E6/E7 mRNA testings (interims of sensitivity, specificity, negative and positive predictive values) for the detection of CIN2+. Results: Out of 231 applicable citations, we have included 29 articles with a total of 23,576 study participants (age range, 15-84) who had different cervical pathologies. Among the participants who had cervical histology, the proportion of CIN2+ was between 10.6% and 90.6%. Using histology as a gold standard, 11 studies evaluated the PreTect HPV Proofer, 7 studies evaluated the APTIMA HPV assay (Gen-Probe) and 6 studies evaluated the Quantivirus® HPV assay. The diagnostic performance of those three most common mRNA testing tools to detect CIN2+ was; 1) PreTect Proofer; median sensitivity 83%, median specificity 73%, median PPV 70 and median NPV 88.9%. 2) APTIMA assay; median sensitivity 91.4%, median specificity 46.2%, median PPV 34.3% and median NPV 96.3%. 3) Quantivirus®: median sensitivity 86.1%, median specificity 54.6%, median PPV 54.3%, median NPV 89.3%. Further, the area under the receiver operating characteristics (AU-ROC) curve varied between 63.8% and 90.9%. Conclusions: The reported diagnostic accuracy implies that mRNA tests possess diagnostic relevance to detect CIN2+ and could potentially be considered in areas where there is no histology facility. Further studies including its cost should be considered.

Diagnostic Accuracy of Increased Mean Platelet Volume as Inflammatory Marker in Diagnosis of Acute Appendicitis Taking Histopathology as Gold Standard

2021 ◽  
Vol 15 (10) ◽  
pp. 2790-2792
Author(s):  
Hina Rehman Siddiqui ◽  
Tahira Tariq ◽  
Samar Babiker Awadallah Omer ◽  
Nadia Rizvi
Keyword(s):  
Acute Appendicitis ◽  
Diagnostic Accuracy ◽  
Gold Standard ◽  
Mean Platelet Volume ◽  
Inflammatory Marker ◽  
Total Leukocyte Count ◽  
Platelet Volume ◽  
Duration Of Symptoms ◽  
Predictive Values ◽  
Sensitivity Specificity

Objective: To determine diagnostic accuracy of increased mean platelet volume as inflammatory marker in diagnosis of acute appendicitis taking histopathology as gold standard. Study Design: Cross Sectional Study. Setting: Department of Surgery, Abbasi Shaheed Hospital, Karachi. Duration: From 28th October 2016 To 27thApril 2017. Material and Methods: Total 229patients suffered from acute appendicitis were included. Venous blood (<20 ml) for complete blood count was sent to lab before surgery. MPV >11fl was taken as increased value. Post-appendicectomy appendix was sent for histopathology. Sensitivity, specificity, positive and negative predictive values were calculated. Stratification was done. Chi-square test was applied post stratification and p-value ≤0.05 was considered as significant. Results: There were 128 male and 101 female. Mean age was 34.09±6.63 years. Mean duration of symptoms was 28.97±11.89 hours. 107 patients were observed with total leukocyte count >10X103µL. Mean platelets volume was more than 11 fl in 47.2% patients. Sensitivity, Specificity, PPV, NPV and accuracy were 74.6%, 91.6%, 92.5%, 71.9%, and 81.6% respectively. Conclusion: In conclusion in patients with temporary diagnosis of acute appendicitis, high MPV “≥ 11fl” can assist in the identification of acute appendicitis hence negative rate of appendectomy can be decreased.. Keywords: Diagnostic Accuracy, Increased Mean Platelet Volume, Acute Appendicitis, Histopathology

Cuff Leak Test for the Diagnosis of Post-Extubation Stridor: A Multicenter Evaluation Study

2017 ◽  
Vol 34 (5) ◽  
pp. 391-396 ◽  
Author(s):  
David Schnell ◽  
Benjamin Planquette ◽  
Asaël Berger ◽  
Sybille Merceron ◽  
Julien Mayaux ◽  
...  
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Diagnostic Performance ◽  
Prolonged Mechanical Ventilation ◽  
Evaluation Study ◽  
High Rate ◽  
Leak Test ◽  
Predictive Values ◽  
Cuff Leak ◽  
Multicenter Prospective Study

Background: Cuff leak test was developed to predict the occurrence of post-extubation stridor (PES). This study evaluated the diagnostic performance of this test in unselected critically ill patients. Methods: Multicenter prospective study including unselected ventilated patients at the time of their first planned extubation. The diagnostic performance of 4 different cuff leak tests was assessed. Results: Post-extubation stridor occurred in 34 (9.4%) of 362 included patients. Compared to patients without PES, patients with PES required more frequently reintubation (6 [17.6%] vs 26 [7.9%], P = .041), prolonged duration of ventilation (6 [3-13] vs 5 [2-9] days, P = .029), and longer intensive care unit (ICU) stay (12 [6-17.5] vs 7.5 [4-13] days, P = .018). However, ICU mortality was similar in both groups (1 [2.9%] vs 23 [7.0%], P = .61). The 4 cuff leak tests display poor diagnostic accuracy: sensitivities ranging from 27% to 46%, specificities from 70% to 88%, positive predictive values from 14% to 19%, and negative predictive values from 92% to 93%. Conclusion: Post-extubation stridor occurs in less than 10% of unselected critically ill patients. The several cuff leak tests display limited diagnostic performance for the detection of PES. Given the high rate of false positives, routine cuff leak test may expose to undue prolonged mechanical ventilation.

Routine non-thyroid head and neck cytology in a large UK centre: clinical utility and pitfalls

2015 ◽  
Vol 129 (7) ◽  
pp. 682-687
Author(s):  
P V Kaye ◽  
M Pigera ◽  
M M Khan ◽  
P Hollows ◽  
N Beasley
Keyword(s):  
Diagnostic Accuracy ◽  
Head And Neck ◽  
Reporting System ◽  
Needle Aspiration ◽  
High Rate ◽  
University Hospitals ◽  
Predictive Values ◽  
The Absolute ◽  
Sensitivity Specificity

AbstractObjective:This study aimed to examine the performance of head and neck cytology at Nottingham University Hospitals between 2009 and 2010.Methods:Cases were extracted from the Winpath pathology reporting system and correlations were investigated between results and the histological and clinical outcomes. Specimen adequacy and the sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of the cytology tests were calculated.Results:In all, 19.7 per cent of aspirates were judged to be inadequate. The absolute and relative sensitivities of head and neck cytology were 87.0 per cent and 89.0 per cent, respectively, and the absolute and relative specificities were 99.0 per cent and 97.0 per cent, respectively. The positive predictive values were 99.0 per cent and 96.0 per cent and the negative predictive values were 92.0 per cent and 92.0 per cent for a diagnostic accuracy of 94.5 per cent and 93.0 per cent. The performance was consistent with previous reports and superior to that of a recent UK series. The high rate of inadequate samples is, however, a concern.Conclusion:Head and neck cytology is a robust technique at our institution, although there are certain problem areas. There is room for improvement in the technical quality of fine needle aspiration.

scholarly journals Analytical and Clinical Performance of the Panbio COVID-19 Antigen-Detecting Rapid Diagnostic Test

2020 ◽  
Author(s):  
Andrea Alemany ◽  
Bàrbara Baro ◽  
Dan Ouchi ◽  
Maria Ubals ◽  
Marc Corbacho-Monné ◽  
...  
Keyword(s):  
Viral Load ◽  
High Risk ◽  
Diagnostic Accuracy ◽  
Diagnostic Performance ◽  
Clinical Performance ◽  
Point Of Care ◽  
Routine Practice ◽  
Reference Test ◽  
Predictive Values ◽  
Asymptomatic Individuals

AbstractBackgroundThe current standard for COVID-19 diagnosis, RT-qPCR, has important drawbacks for its use as a tool for epidemiological control, including the need of laboratory-processing, high cost, and long turnaround from sampling to results release. Antigen-based rapid diagnostic tests (Ag-RDT) provide a promising alternative for this purpose.MethodsWe assessed the analytical and clinical performance of the Ag-RDT Panbio COVID-19 Ag Test (Abbott), using RT-qPCR as a reference test. The clinical performance was assessed using nasopharyngeal swabs, collected in routine practice for case confirmation and contact tracing, and nasal mid-turbinate swabs, collected in preventive screenings of asymptomatic individuals. Fresh samples were analysed by RT-q-PCR, stored at -80 °C, and analysed using the Ag-RDT according to the manufacturer instructions.FindingsThe Ag-RDT had a limit of detection of 6·5×105 copies/reaction. The clinical performance was assessed on 1,406 frozen swabs with a PCR result available: 951 (67·7%) positive and 455 (32·4%) negative. The Ag-RDT identified the presence of SARS-CoV-2 in 872 of 951 PCR-positive samples (91·7%; 95% CI 89·8-93·4 and ruled out its presence in 450 of 455 PCR-negative samples (specificity 98·9%; 95% CI 97·5– 99·6). Sensitivity increased in samples with lower Ct values (Ct <25, 98·2%; Ct<30, 94·9%) and was higher among symptomatic cases (92·6%) and their contacts (94·2%) than among asymptomatic individuals (79·5%). In the setting of asymptomatic screening, sensitivity also increased with lower Ct values (Ct <25, 100%; Ct<30, 98·6%). Assuming a pre-test probability of 5%, the negative and positive predictive values were 99·6% (99·5 – 99·6) and 81·5% (65·0 – 93·2), respectively.InterpretationThe Panbio COVID-19 Ag-RDT has high sensitivity for detecting the presence of SARS-CoV-2 in nasal or nasopharyngeal swabs of both, symptomatic and asymptomatic individuals. The diagnostic performance of the test is particularly good in samples with viral loads associated with high risk of viral transmission (Ct <25), which show high positive and negative predictive values even when assuming a prevalence as low as 5%.FundingBlueberry diagnostics, Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, and #YoMeCorono.org crowfunding campaing.Research in contextEvidence before this studyOn October 6, 2020, we searched PubMed for articles containing “Antigen”, “test”, “SARS-CoV-2”, “COVID-19” and “performance” in either the title or the abstract. We found five studies that showed the accuracy of point-of-care tests in identifying SARS-CoV-2 antigens for confirmation of clinically suspected COVID-19. We found high variability in the diagnostic accuracy of Ag-RDT. Most tests showed high specificity (i.e., 99% or higher), whereas sensitivity ranged from 11% to 92%; only one test reported sensitivity higher than 60%. We found no studies investigating the diagnostic accuracy of the Panbio COVID-19 Ag Test. We found no studies that assessed the performance of Ag-RDT for population-level screening of asymptomatic individuals.Added value of this studyOur analysis provides information regarding the diagnostic accuracy of the Panbio COVID-19 Ag Test when tested on 1,406 frozen samples of nasopharyngeal and nasal swabs collected in routine practice for diagnostic confirmation of symptomatic individuals with suspected COVID-19 or contacts exposed to a positive case, and preventive screenings of unexposed asymptomatic individuals. Compared with RT-qPCR as reference test, the Ag-RDT showed a sensitivity and specificity of 91·7% and 98·9%. Test sensitivity increased in samples with viral load associated with high risk of transmission (Ct <25), reaching more than 98%, regardless of the presence of symptoms.Implications of all the available evidenceAvailable evidence show variability in the diagnostic performance of marketed Ag-RDT. Our results provide substantial evidence that the point-of-care Panbio COVID-19 Ag Test can accurately identify SARS-CoV-2 antigens in people with suspected clinical COVID-19 as well as in asymptomatic people with high viral load and therefore, associated with higher risk of transmission. This finding represents a potentially useful advance for mass screening of asymptomatic people at the point-of-care.

scholarly journals New technologies for diagnosing active TB: the VANTDET diagnostic accuracy study

2021 ◽  
Vol 8 (5) ◽  
pp. 1-160
Author(s):  
Alice Halliday ◽  
Pooja Jain ◽  
Long Hoang ◽  
Robert Parker ◽  
Mica Tolosa-Wright ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Flow Cytometry ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Diagnostic Performance ◽  
New Technologies ◽  
Predictive Values ◽  
Qrt Pcr ◽  
Life Years ◽  
Positive Population

Background Tuberculosis (TB) is a devastating disease for which new diagnostic tests are desperately needed. Objective To validate promising new technologies [namely whole-blood transcriptomics, proteomics, flow cytometry and quantitative reverse transcription-polymerase chain reaction (qRT-PCR)] and existing signatures for the detection of active TB in samples obtained from individuals with suspected active TB. Design Four substudies, each of which used samples from the biobank collected as part of the interferon gamma release assay (IGRA) in the Diagnostic Evaluation of Active TB study, which was a prospective cohort of patients recruited with suspected TB. Setting Secondary care. Participants Adults aged ≥ 16 years presenting as inpatients or outpatients at 12 NHS hospital trusts in London, Slough, Oxford, Leicester and Birmingham, with suspected active TB. Interventions New tests using genome-wide gene expression microarray (transcriptomics), surface-enhanced laser desorption ionisation time-of-flight mass spectrometry/liquid chromatography–mass spectrometry (proteomics), flow cytometry or qRT-PCR. Main outcome measures Area under the curve (AUC), sensitivity and specificity were calculated to determine diagnostic accuracy. Positive and negative predictive values were calculated in some cases. A decision tree model was developed to calculate the incremental costs and quality-adjusted life-years of changing from current practice to using the novels tests. Results The project, and four substudies that assessed the previously published signatures, measured each of the new technologies and performed a health economic analysis in which the best-performing tests were evaluated for cost-effectiveness. The diagnostic accuracy of the transcriptomic tests ranged from an AUC of 0.81 to 0.84 for detecting all TB in our cohort. The performance for detecting culture-confirmed TB or pulmonary TB was better than for highly probable TB or extrapulmonary tuberculosis (EPTB), but was not high enough to be clinically useful. None of the previously described serum proteomic signatures for active TB provided good diagnostic accuracy, nor did the candidate rule-out tests. Four out of six previously described cellular immune signatures provided a reasonable level of diagnostic accuracy (AUC = 0.78–0.92) for discriminating all TB from those with other disease and latent TB infection in human immunodeficiency virus-negative TB suspects. Two of these assays may be useful in the IGRA-positive population and can provide high positive predictive value. None of the new tests for TB can be considered cost-effective. Limitations The diagnostic performance of new tests among the HIV-positive population was either underpowered or not sufficiently achieved in each substudy. Conclusions Overall, the diagnostic performance of all previously identified ‘signatures’ of TB was lower than previously reported. This probably reflects the nature of the cohort we used, which includes the harder to diagnose groups, such as culture-unconfirmed TB or EPTB, which were under-represented in previous cohorts. Future work We are yet to achieve our secondary objective of deriving novel signatures of TB using our data sets. This was beyond the scope of this report. We recommend that future studies using these technologies target specific subtypes of TB, specifically those groups for which new diagnostic tests are required. Funding This project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a MRC and NIHR partnership.

scholarly journals Diagnostic performance of CareStart™ malaria HRP2/pLDH test in comparison with standard microscopy for detection of uncomplicated malaria infection among symptomatic patients, Eastern Coast of Tanzania

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
George M. Bwire ◽  
Billy Ngasala ◽  
Manase Kilonzi ◽  
Wigilya P. Mikomangwa ◽  
Fatuma F. Felician ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Parasite Density ◽  
Diagnostic Performance ◽  
Geometric Mean ◽  
Health Care Facilities ◽  
Eastern Coast ◽  
Predictive Values ◽  
Number Of Patients ◽  
Sensitivity Specificity ◽  
Strong Agreement

Abstract Background CareStart™ malaria HRP2/pLDH (Pf/pan) combo test is one of the several rapid diagnostic tests (RDT) approved for diagnosis of malaria at the point of care in Tanzania. However, there are limited studies on the diagnostic performance of RDT after wide scale use in primary health care facilities in Tanzania. Therefore, this study was carried out to determine the diagnostic performance of RDT when compared with blood smear (BS) microscopy as a reference standard. Methods A cross-sectional study was conducted between March and August 2019 at Kibiti Health Centre, Pwani region, Tanzania. Blood samples for malaria tests were collected from patients with malaria symptoms. Diagnostic performance parameters of RDT, i.e. sensitivity, specificity, positive and negative likelihood ratios (LR+/−), diagnostic accuracy and predictive values were determined using contingency table. An agreement between RDT and microscopy was statistically determined by Cohen’s kappa test. Results Of 980 patients screened, 567 (57.9%) were found to be malaria positive by RDT, whereas 510 patients (52%) were positive by microscopy. Of the 510 microscopy-positive patients, 487 (95.5%) were infected with Plasmodium falciparum. The geometric mean parasite density was 2921parasites/µl, whereas majority (68.6%) of patients had parasite density greater than 10,000/µl. The sensitivity, specificity, positive and negative predictive values of CareStart™ were 99.8%, 87.6%, 89.8%, and 99.8%, respectively. The LR+ and LR− were 8.0 and 0.002, respectively. The diagnostic accuracy was 0.5. There was a strong agreement between the results obtained using CareStart™ and BS microscopy (kappa = 0.863, P < 0.0001). Conclusion CareStart™ malaria HRP2/pLDH (Pf/pan) had high sensitivity and strong agreement with microscopy results. However, moderate specificity of RDT resulted in a substantial number of patients with false positive malaria test. Wherever available, microscopy should be used to confirm RDT test results.

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