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 Modelling the epidemiology of malaria and spread of HRP2-negative Plasmodium falciparum following the replacement of HRP2-detecting rapid diagnostic tests

2022 ◽  
Vol 2 (1) ◽  
pp. e0000106
Author(s):  
Alisha Chaudhry ◽  
Jane Cunningham ◽  
Qin Cheng ◽  
Michelle L. Gatton
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Tests ◽  
False Negative ◽  
Parasite Prevalence ◽  
Rapid Diagnostic Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Malaria Rapid Diagnostic Tests ◽  
The Impact

Malaria rapid diagnostic tests (RDTs) are dominated by products which use histidine-rich protein 2 (HRP2) to detect Plasmodium falciparum. The emergence of parasites lacking the pfhrp2 gene can lead to high rates of false-negative results amongst these RDTs. One solution to restore the ability to correctly diagnose falciparum malaria is to switch to an RDT which is not solely reliant on HRP2. This study used an agent-based stochastic simulation model to investigate the impact on prevalence and transmission caused by switching the type of RDT used once false-negative rates reached pre-defined thresholds within the treatment-seeking symptomatic population. The results show that low transmission settings were the first to reach the false-negative switch threshold, and that lower thresholds were typically associated with better long-term outcomes. Changing the diagnostic RDT away from a HRP2-only RDT is predicted to restore the ability to correctly diagnose symptomatic malaria infections, but often did not lead to the extinction of HRP2-negative parasites from the population which continued to circulate in low density infections, or return to the parasite prevalence and transmission levels seen prior to the introduction of the HRP2-negative parasite. In contrast, failure to move away from HRP2-only RDTs leads to near fixation of these parasites in the population, and the inability to correctly diagnose symptomatic cases. Overall, these results suggest pfhrp2-deleted parasites are likely to become a significant component of P. falciparum parasite populations, and that long-term strategies are needed for diagnosis and surveillance which do not rely solely on HRP2.

scholarly journals Visualization of Lesions of Metaphyses and Epiphyses of Bones in Newborns and Young Children

2021 ◽  
pp. 82-90
Author(s):  
N. A. Sholokhova
Keyword(s):  
Young Children ◽  
False Negative ◽  
Age Groups ◽  
High Sensitivity ◽  
Negative Results ◽  
False Negative Results ◽  
Inflammatory Processes ◽  
Group 5 ◽  
Magnetic Resonance Imaging Mri ◽  
Diagnostic Capabilities

The aim of this study was to determine the diagnostic capabilities of various methods of radiological diagnostics for lesions of the metaphyses and epiphyses of bones in newborns and young children.The study involved 108 children in the age group 5 days – 12 months with pathological changes in the pineal gland and bone metaphysis. The possibilities and advantages of standard radiography (СR), ultrasound examination (US) and magnetic resonance imaging (MRI) in the early and differential diagnosis of the osteomyelitis process and epiphyseolysis have been determined. High sensitivity (98 %), specificity (99 %) and accuracy (98 %) for ultrasound and sensitivity (94 %), specificity (89 %) and accuracy (95 %) of MRI in diagnosing osteomyelitis in patients of this age groups. At the same time, the possibilities of standard radiography at the stages of early diagnosis of inflammatory processes in the distal parts of the bones were limited due to a number of factors. The use of diagnostic algorithms greatly facilitates the work of a radiologist and reduces the number of false negative results during the initial treatment of patients.

CLINICAL APPLICATION OF COVID-19 REPORTING AND DATA SYSTEM IN COMPUTED TOMOGRAPHY OF BILATERAL PNEUMONIA DIAGNOSTIC

2021 ◽  
Vol 31 (4) ◽  
pp. 40-45
Author(s):  
Ugnė Kulnickaitė ◽  
Laura Dobrovaitė ◽  
Kamilė Grigaitė ◽  
Edvardas Jukna
Keyword(s):  
Computed Tomography ◽  
False Negative ◽  
High Sensitivity ◽  
Chest Ct ◽  
Data System ◽  
Negative Results ◽  
Radiological Society ◽  
Evaluation Scheme ◽  
False Negative Results ◽  
Standardized Reporting

Background: the 2019 coronavirus disease pandemic (COVID-19) has spread at an astonishing speed across the world, causing major morbidity and mortality. Computed tomography (CT) examination plays an important role in crisis areas in the diagnosis of COVID-19. COVID-19 Reporting and Data System (CO-RADS) has a five-point scale of suspicion for COVID-19 pneumonia in chest CT picture which standardizes the evaluation scheme and simplifies reporting. Aim: to summarise and present the role of COVID-19 Reporting and Data System in computed tomography of bilateral pneumonia diagnostic. Materials and methods: recently published studies were reviewed to evaluate COVID-19 Reporting and Data System scale as effective tool to detect COVID-19 pneumonia on chest CT scans. Databases from the subscription list of Lithuanian University of Health Sciences were selected: Medline (PubMed), SpringerLink and ScienceDirect. Results: chest CT features, as bilateral involvement, subpleural or peripherally distributed GGO, consolidation, reticulation, crazy paving pattern, air bronchogram signs, intralobular septal thickening, pulmonary vascular enlargement, are considered to be characteristic manifestations of COVID-19 infection. Studies show that Dutch Radiological Society presented CO-RADS scale sensitivity and specificity may vary from 61-88% and 66,4-98%, respectively. Conclusion: chest CT scan has a high sensitivity for COVID-19 diagnosis and could reduce false negative results obtained from RT-PCR tests. Furthermore, a standardized reporting system could increase clarification, minimize reporting variability and help radiologists recognize the results they observe, especially, for less experienced specialists.

Pearls and Pitfalls of Interpretation in CT Colonography

2020 ◽  
Vol 71 (2) ◽  
pp. 140-148
Author(s):  
Michael Schonberger ◽  
Philippe Lefere ◽  
Abraham H. Dachman
Keyword(s):  
Computed Tomography ◽  
Sensitivity And Specificity ◽  
False Positive ◽  
Ct Colonography ◽  
False Negative ◽  
High Sensitivity ◽  
Negative Results ◽  
False Negative Results ◽  
The Common

The accuracy of computed tomography (CT) colonography (CTC) requires that the radiologist be well trained in the recognition of pitfalls of interpretation. In order to achieve a high sensitivity and specificity, the interpreting radiologist must be well versed in the causes of both false-positive and false-negative results. In this article, we review the common and uncommon pitfalls of interpretation in CTC.

scholarly journals Cell-free DNA screening for aneuploidies in 7113 pregnancies: single Italian centre study

2020 ◽  
Vol 102 ◽  
Author(s):  
Alvaro Mesoraca ◽  
Katia Margiotti ◽  
Claudio Dello Russo ◽  
Anthony Cesta ◽  
Antonella Cima ◽  
...  
Keyword(s):  
Sex Chromosome ◽  
Clinical Performance ◽  
False Negative ◽  
Prenatal Testing ◽  
High Sensitivity ◽  
Trisomy 13 ◽  
Sequencing Platform ◽  
Non Invasive ◽  
Negative Results ◽  
False Negative Results

Abstract Introduction Non-invasive prenatal testing (NIPT) using cell-free foetal DNA has been widely accepted in recent years for detecting common foetal chromosome aneuploidies, such as trisomies 13, 18 and 21, and sex chromosome aneuploidies. In this study, the practical clinical performance of our foetal DNA testing was evaluated for analysing all chromosome aberrations among 7113 pregnancies in Italy. Methods This study was a retrospective analysis of collected NIPT data from the Ion S5 next-generation sequencing platform obtained from Altamedica Medical Centre in Rome, Italy. Results In this study, NIPT showed 100% sensitivity and 99.9% specificity for trisomies 13, 18 and 21. Out of the 7113 samples analysed, 74 cases (1%) were positive by NIPT testing; foetal karyotyping and follow-up results validated 2 trisomy 13 cases, 5 trisomy 18 cases, 58 trisomy 21 cases and 10 sex chromosome aneuploidy cases. There were no false-negative results. Conclusion In our hands, NIPT had high sensitivity and specificity for common chromosomal aneuploidies such as trisomies 13, 18 and 21.

scholarly journals Validity of protein-creatinine and protein-osmolality ratios in the estimation of massive proteinuria in children with nephrotic syndrome

2007 ◽  
Vol 47 (4) ◽  
pp. 139
Author(s):  
M. Sukmawati ◽  
K. Suarta
Keyword(s):  
Nephrotic Syndrome ◽  
Predictive Value ◽  
Diagnostic Tests ◽  
Quantitative Methods ◽  
False Negative ◽  
Creatinine Ratio ◽  
Negative Results ◽  
False Negative Results ◽  
Sensitivity Specificity ◽  
Posttest Probability

Background Children with nephrotic syndrome have massiveproteinuria, a rate of excretion equal to or greater than 40 mg/hour/m 2 body surface. The ability to quantitate massive urinaryprotein excretion is very important for both diagnostic andprognostic purposes. Quantification of proteinuria using 24-hoururine collection (Esbach) is difficult to do especially in children;moreover, many false-positive and false-negative results arereported for any semi-quantitative methods such as dipstick andsulfosalicylic acid measurement.Objective To determine the accuracy of protein-creatinine ratio(PCR) and protein-osmolality ratio (POR) in quantification ofmassive proteinuria in children with nephrotic syndrome.Methods Diagnostic tests were conducted on children withnephrotic syndrome aged 2-12 years with Esbach as a referencestandard. Sensitivity, specificity, positive predictive value (PPV),negative predictive value, (NPV), pre and posttest probabilitywere compared between PCR and POR.Results Study patients consisted of 47 children, 38 (81%) withmassive proteinuria. PCR has sensitivity of 92%, specificity of78%, PPV of 95%, NPV of 70% and posttest probability of 95%.POR has sensitivity of 76%, specificity of 78%, PPV of 94%, NPVof 44% and posttest probability of 94%.Conclusion Both PCR and POR are accurate to determine massiveproteinuria in children with nephrotic syndrome.

scholarly journals Unexplained False Negative Results in Noninvasive Prenatal Testing: Two Cases Involving Trisomies 13 and 18

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
R. Hochstenbach ◽  
G. C. M. L. Page-Christiaens ◽  
A. C. C. van Oppen ◽  
K. D. Lichtenbelt ◽  
J. J. T. van Harssel ◽  
...  
Keyword(s):  
False Negative ◽  
Prenatal Testing ◽  
High Sensitivity ◽  
Trisomy 13 ◽  
Maternal Weight ◽  
Noninvasive Prenatal Testing ◽  
Root Cause ◽  
Negative Results ◽  
False Negative Results ◽  
Negative Case

Noninvasive prenatal testing (NIPT) validation studies show high sensitivity and specificity for detection of trisomies 13, 18, and 21. False negative cases have rarely been reported. We describe a false negative case of trisomy 13 and another of trisomy 18 in which NIPT was commercially marketed directly to the clinician. Both cases came to our attention because a fetal anatomy scan at 20 weeks of gestation revealed multiple anomalies. Karyotyping of cultured amniocytes showed nonmosaic trisomies 13 and 18, respectively. Cytogenetic investigation of cytotrophoblast cells from multiple placental biopsies showed a low proportion of nontrisomic cells in each case, but this was considered too small for explaining the false negative NIPT result. The discordant results also could not be explained by early gestational age, elevated maternal weight, a vanishing twin, or suboptimal storage or transport of samples. The root cause of the discrepancies could, therefore, not be identified. The couples involved experienced difficulties in accepting the unexpected and late-adverse outcome of their pregnancy. We recommend that all parties involved in caring for couples who choose NIPT should collaborate to clarify false negative results in order to unravel possible biological causes and to improve the process of patient care from initial counseling to communication of the result.

scholarly journals Assessment of the IgA Immunoassay Diagnostic Potential of the Mycobacterium tuberculosis MT10.3-MPT64 Fusion Protein in Tuberculous Pleural Fluid

2010 ◽  
Vol 17 (12) ◽  
pp. 1963-1969 ◽  
Author(s):  
Leonardo Silva Araujo ◽  
Renata Maciel Moraes ◽  
Anete Trajman ◽  
Maria Helena Féres Saad
Keyword(s):  
Pleural Fluid ◽  
Histopathological Examination ◽  
False Negative ◽  
High Sensitivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Negative Results ◽  
Diagnostic Potential ◽  
False Negative Results ◽  
Sds Page ◽  
Increased Sensitivity

ABSTRACT Pleural tuberculosis (PL-TB) remains difficult to diagnose. An enzyme-linked immunosorbent assay (ELISA) was developed based on a construction containing the fusion of the Rv3019c (MT10.3) and Rv1980c (MPT64) gene sequences, and its performance was evaluated in an area where TB is endemic. A total of 92 pleural fluid (PF) samples at serial dilutions of 1:50 to 1:800 were included in the ELISA IgA MT10.3-MPT64 evaluation: 70 from TB patients and 22 from patients with other pleurisies. Confirmation of the expression and subsequent purification of the protein was made by SDS-PAGE and Western blot assays, resulting in a 36-kDa protein. ELISA IgA MT10.3-MPT64 showed sensitivities of 61.4%, 58.6%, 62.9%, 67.1%, and 70% at each PF dilution, respectively. The cumulative results of all dilutions increased sensitivity to 81.4% without jeopardizing specificity. Similar results were also obtained at the combined dilutions of 1:50, 1:200, and 1:800 or 1:50 plus 1:800 dilutions (80%). The overall sensitivity of the reference test, i.e., histopathological examination, was 74%. But, via the ELISA IgA MT10.3-MPT64 test, sensitivity was high for specimens with a negative culture (23/27; 85.2%) or nonspecific histopathology (17/18; 94.4%). Our findings demonstrated the promising use of this test as an adjunct in PL-TB diagnoses, particularly in cases with lower bacterial loads and false-negative results in the reference tests, since the new test includes such important features as quick and easy application, high sensitivity and, perhaps most importantly, affordability, which is so crucial for its widespread use in developing countries.

Role and limits of testicular phleboscintigraphy in the diagnostic evaluation of varicocele

1994 ◽  
Vol 61 (2) ◽  
pp. 98-102
Author(s):  
A. Raimoldi ◽  
G.L. Berti ◽  
V. Giola ◽  
G.L. Leidi ◽  
A. Maccaroni ◽  
...  
Keyword(s):  
Doppler Ultrasonography ◽  
Low Cost ◽  
False Negative ◽  
High Sensitivity ◽  
Diagnostic Evaluation ◽  
Ultrasound Technique ◽  
Negative Results ◽  
False Negative Results ◽  
First Choice ◽  
Choice Method

The Authors wanted to check the reliability of testicular phleboscintigraphy in the diagnostic evaluation of varicocele, comparing it to Doppler ultrasonography. To this end, 98 patients affected by clinically evident left idiopathic varicocele were tested. The two methods gave equivalent results in all patients affected by 2nd and 3rd clinical degree varicocele, while testicular phleboscintigraphy gave false negative results in 7 patients with 1st degree varicocele, due to renospermatic retrograde flow. Therefore, in the Authors' opinion, the Doppler ultrasound technique can be considered as a first choice method in the study of varicocele, thanks to its high sensitivity associated with low cost, whereas testicular phleboscintigraphy can be used either when Doppler ultrasonography evaluation is not reliable or as a second examination to confirm the Doppler results, especially in patients with 2nd and 3rd clinical degree varicocele.

scholarly journals Limitations of rapid diagnostic tests in malaria surveys in areas with varied transmission intensity in Uganda 2017-2019: Implications for selection and use of HRP2 RDTs

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244457
Author(s):  
Agaba B. Bosco ◽  
Joaniter I. Nankabirwa ◽  
Adoke Yeka ◽  
Sam Nsobya ◽  
Karryn Gresty ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Gene Deletion ◽  
False Negative ◽  
Malaria Diagnosis ◽  
Dried Blood Spots ◽  
Rapid Diagnostic Tests ◽  
Low Density ◽  
Related Factors ◽  
Cross Sectional ◽  
Factors Associated

Background Plasmodium falciparum histidine-rich protein 2 (HRP2)-based rapid diagnostic tests (RDTs) are exclusively recommended for malaria diagnosis in Uganda; however, their functionality can be affected by parasite-related factors that have not been investigated in field settings. Methods Using a cross-sectional design, we analysed 219 RDT-/microscopy+ and 140 RDT+/microscopy+ dried blood spots obtained from symptomatic children aged 2–10 years from 48 districts in Uganda between 2017 and 2019. We aimed to investigate parasite-related factors contributing to false RDT results by molecular characterization of parasite isolates. ArcGIS software was used to map the geographical distribution of parasites. Statistical analysis was performed using chi-square or Fisher’s exact tests, with P ≤ 0.05 indicating significance. Odds ratios (ORs) were used to assess associations, while logistic regression was performed to explore possible factors associated with false RDT results. Results The presence of parasite DNA was confirmed in 92.5% (332/359) of the blood samples. The levels of agreement between the HRP2 RDT and PCR assay results in the (RDT+/microscopy+) and (RDT-/microscopy+) sample subsets were 97.8% (137/140) and 10.9% (24/219), respectively. Factors associated with false-negative RDT results in the (RDT-/microscopy+) samples were parasite density (<1,000/μl), pfhrp2/3 gene deletion and non-P. falciparum species (aOR 2.65, 95% CI: 1.62–4.38, P = 0.001; aOR 4.4, 95% CI 1.72–13.66, P = 0.004; and aOR 18.65, 95% CI: 5.3–38.7, P = 0.001, respectively). Overall, gene deletion and non-P. falciparum species contributed to 12.3% (24/195) and 19.0% (37/195) of false-negative RDT results, respectively. Of the false-negative RDTs results, 80.0% (156/195) were from subjects with low-density infections (< 25 parasites per 200 WBCs or <1,000/μl). Conclusion This is the first evaluation and report of the contributions of pfhrp2/3 gene deletion, non-P. falciparum species, and low-density infections to false-negative RDT results under field conditions in Uganda. In view of these findings, the use of HRP2 RDTs should be reconsidered; possibly, switching to combination RDTs that target alternative antigens, particularly in affected areas, may be beneficial. Future evaluations should consider larger and more representative surveys covering other regions of Uganda.

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