Performance evaluation of the highly sensitive histidine‐rich protein 2 rapid test for Plasmodium falciparum malaria in North-West Tanzania

Abstract Background Precise detection of Plasmodium infections in community surveys is essential for effective malaria control. Microscopy and rapid diagnostic tests (RDTs) are the major techniques used to identify malaria infections in the field-based surveys. Although microscopy is still considered as the gold standard, RDTs are increasingly becoming versatile due to their rapid and adequate performance characteristics. Methods A malaria prevalence cross-sectional survey was carried out in north-western Tanzania in 2016, aimed at appraising the performance of high sensitivity Plasmodium falciparum (HSPf) tests compared to SD Bioline Pf and microscopy in detecting P. falciparum infections. A total of 397 individuals aged five years and above were tested for P. falciparum infections. The sensitivity, specificity, positive, and negative predictive values (PPV and NPV) of microscopy, Pf RDT and HSPf RDT was determined using PCR as the gold standard method. Results The prevalence of P. falciparum infections determined by microscopy, SD Bioline Pf, HSPf and PCR was 21.9, 27.7, 33.3 and 43.2%, respectively. The new HSPf RDT had significantly higher sensitivity (98.2%) and specificity (91.6%) compared to the routinely used SD Bioline Pf RDT(P < 0.001). The positive predictive value (PPV) was 81.8% and the negative predictive value (NPV) was 99.2% for the routinely used SD Bioline Pf RDT. Moreover, HSPf RDT had sensitivity of 69% and specificity of 76.8% compared to microscopy. The PPV was 45.5% and the NPV was 89.8% for microscopy. Furthermore, the analytical sensitivity test indicated that the newly developed HSPf RDT had lower detection limits compared to routinely used SD Bioline RDT. Conclusions HSPf RDT had better performance when compared to both microscopy and the currently used malaria RDTs. The false negativity could be associated with the low parasite density of the samples. False positivity may be related to the limitations of the expertise of microscopists or persistent antigenicity from previous infections in the case of RDTs. Nevertheless, HS PfRDT performed better compared to routinely used Pf RDT, and microscopy in detecting malaria infections. Therefore, HS Pf RDT presents the best alternative to the existing commercial/regularly available RDTs due to its sensitivity and specificity, and reliability in diagnosing malaria infections.

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Comparison of Hay’s Criteria with Nugent’s Scoring System for Diagnosis of Bacterial Vaginosis

BioMed Research International ◽

10.1155/2013/365194 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 9

Author(s):

Rohit Chawla ◽

Preena Bhalla ◽

Sanjim Chadha ◽

Sujatha Grover ◽

Suneela Garg

Keyword(s):

Bacterial Vaginosis ◽

Predictive Value ◽

Gold Standard ◽

Tertiary Care ◽

Gold Standard Method ◽

Predictive Values ◽

Intermediate Group ◽

Kappa Value ◽

Grade Ii ◽

Sensitivity Specificity

Although Nugent’s criterion is considered as the gold standard for the diagnosis of bacterial vaginosis (BV), the method requires an experienced slide reader and considerable time and skill. In this study, we compared the method of Hay and Ison with Nugent’s scoring criteria. Vaginal specimens were collected from a total of 213 women, presenting with or without the symptoms of vaginitis. Diagnosis of BV was done using Nugent’ and Hay’s method. Sensitivity, specificity, and predictive values for positive and negative test were calculated for Hay’s method using Nugent’s method as the gold standard. We diagnosed 70 cases (32.86%) of BV by Nugent’s method and 87 (40.85%) cases by the Hay’s method. Sensitivity, specificity, predictive value of positive result, predictive value of negative result, and Kappa value when evaluating Hay’s criteria using Nugent’s criteria as the gold standard were ≥97.2%, ≥88.1%, ≥80.4%, ≥97.1%, and ≥0.830, respectively, when Hay’s grade II and/or Nugent’s intermediate score were considered either as negative or positive or excluded. Using Nugent score for the intermediate group is the most difficult. Hay’s method shows good agreement with the gold standard method of Nugent et al. and can be used as an alternative to Nugent’s criteria in busy tertiary care hospitals.

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Positive Predictive Value of MRI in the Diagnosis of Intra-Abdominal Undescended Testes Taking Laparoscopic Findings as Gold Standard

Annals of Punjab Medical College ◽

10.29054/apmc/2021.762 ◽

2021 ◽

Vol 15 (1) ◽

pp. 36-39

Author(s):

Aasia Jehangir ◽

◽

Amber Goraya ◽

Abid Ali Qureshi ◽

◽

...

Keyword(s):

Positive Predictive Value ◽

Predictive Value ◽

False Positive ◽

Gold Standard ◽

Vital Role ◽

True Positive ◽

Undescended Testes ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Non Invasive

Background: Cryptorchidism also known as undescended testis, is a birth defect in male babies with higher frequency in preterm infants, leading infertility and other genital problems. In its treatment, diagnosis has a vital role. Objective: The objective of this study was to determine the positive predictive value of MRI in the diagnosis of intra-abdominal undescended testes taking laparoscopic findings as gold standard. Study Design: It was a cross-sectional survey. Settings: Research was conducted at Department of Diagnostic Radiology, Children Hospital & Institute of Child Health Lahore Pakistan. Duration: Six months from June 23, 2018 to December 22, 2018. Methodology: This study involved 68 boys aged between 2 to 15 years presenting with undescended testes. Intra-abdominal undescended testes were diagnosed on MRI and was later confirmed on laparoscopic findings which were taken as gold standard and diagnosis of MRI was judged accordingly as true positive or false positive. A written informed consent was obtained from parents of every patient. Results: The age of the children ranged from 2 years to 15 years with a mean of 8.1±3.5 years. Majority (n=53, 77.9%) of the children had right while 15 (22.1%) children had left undescended testes. Diagnosis of intra-abdominal testes was confirmed in 64 (94.1%) patients on laparoscopy. Thus, there were 64 true positive and 4 false positive cases. It yielded a positive predictive value of 94.1% for MRI in predicting intra-abdominal undescended testes taking laparoscopy as gold standard. Similar positive predictive value was noted across various age and anatomical side groups. Conclusion: The positive predictive value of MRI was found to be 94.1% in predicting intra-abdominal undescended testes taking laparoscopic findings as gold standard regardless of patient’s age and anatomical side which along with its non-invasive and radiation free nature advocates its preferred use in future practice.

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Bayesian evaluation of the performance of three diagnostic tests for Plasmodium falciparum infection in a low-transmission setting in Kilifi County, Kenya

Wellcome Open Research ◽

10.12688/wellcomeopenres.15204.1 ◽

2019 ◽

Vol 4 ◽

pp. 67

Author(s):

Marshal M. Mweu ◽

Juliana Wambua ◽

Fixtan Njuga ◽

Philip Bejon ◽

Daniel Mwanga

Keyword(s):

Plasmodium Falciparum ◽

Diagnostic Tests ◽

Latent Class ◽

Clinical Care ◽

Latent Class Model ◽

Asymptomatic Malaria ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Predictive Values ◽

Primary Health Care Settings

Background: Central to the successful elimination of Plasmodium falciparum malaria, are tests with superior capability of diagnosing low-density parasitaemias. Empirical evidence on the performance of the commonly available diagnostics (light microscopy (LM), rapid diagnostic tests (RDT) and polymerase chain reaction (PCR)) is needed to better inform case management and surveillance activities within primary health care settings where elimination of falciparum malaria is targeted. The objective of this study was to estimate the sensitivity (Se) and specificity (Sp) and predictive values of LM, RDT and PCR tests for P. falciparum infection, while evaluating the effect of specific covariates on the accuracy of the tests. Methods: The study enrolled 1,563 children via a cross-sectional survey for asymptomatic malaria and those presenting with symptomatic malaria to the Ngerenya dispensary, Kilifi County between March and December 2014. A Bayesian latent class model (BLCM) was fitted to the participants’ diagnostic data obtained from blood samples that were screened for the presence of P. falciparum using the three tests. Results: The PCR assay registered a higher Se (97.6% [92.0; 99.7]) than LM (84.0% [74.8; 91.0]) but similar to RDT (92.2% [84.4; 97.0]). However, the assay showed a similar Sp (98.9% [98.2; 99.4]) to both RDT (99.4% [98.9; 99.7]) and LM (99.5% [99.0; 99.8]). Regarding predictive values, the tests yielded statistically similar estimates of Positive and negative predictive values (PPV and NPV). A serial interpretation of the results of RDT and LM raised the PPVs and NPVs to >98%. Conclusions: LM and RDT tests afford high Se and Sp in a low P. falciparum prevalence setting. A serial combination of the tests assures high PPV and NPV estimates. These elements, coupled with the wide deployment and affordability of the tests, lend the tests useful for guiding clinical care and surveillance activities for P. falciparum within elimination settings.

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Vacuum Dynamics as an Alternative Method for Detection of Bimodal Milk Ejection in Dairy Cows

Animals ◽

10.3390/ani11071860 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1860

Author(s):

Matthias Wieland ◽

Christina Marie Geary ◽

Gloria Gioia ◽

Kerry Lynn Case ◽

Paolo Moroni ◽

...

Keyword(s):

Dairy Cows ◽

Predictive Value ◽

Primary Objective ◽

Cow Milk ◽

Kappa Statistics ◽

Flow Meter ◽

Flow Curves ◽

Cross Sectional ◽

Gold Standard Method ◽

Milk Flow

The primary objective of our study was to assess the ability of a vacuum recorder to detect the presence of bimodal milk flow curves in dairy cows compared with a portable milk flow meter. In a cross-sectional study, 241 individual cow milking observations were analyzed. We simultaneously collected (1) individual cow vacuum events during milking using portable vacuum recorders, and (2) individual cow milk flow curves by attaching a portable milk flow meter to the same milking unit. Presence of bimodality was assessed with the vacuum recorder visually (BIMVA) and with the gold standard method of a milk flow meter through automatic detection (BIMLA). Kappa statistics revealed moderate agreement between BIMVA and BIMLA [κ, 95% confidence intervals (95% CI) = 0.59 (0.46–0.71)]. Diagnostic test statistics for BIMVA for detection of bimodality indicated moderate performance for sensitivity [0.65 (0.52–0.76)] and positive predictive value [0.71 (0.58–0.82)] and high values for specificity [0.92 (0.87–0.95)] and negative predictive value [0.93 (0.84–0.93)]. We conclude that milking vacuum dynamics are a suitable measure to assess bimodal milk flow curves in dairy cows.

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Investigation of the rapid immunochromatographic test performance in the diagnosis of syphilis; comparison of four serological methods

LaboratoriumsMedizin ◽

10.1515/labmed-2019-0012 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Huseyin Agah Terzi ◽

Ozlem Aydemir ◽

Engin Karakece ◽

Huseyin Hatipoglu ◽

Mehmet Olmez ◽

...

Keyword(s):

Test Performance ◽

Gold Standard ◽

Treponema Pallidum ◽

Rapid Test ◽

Immunochromatographic Test ◽

Rapid Plasma Reagin ◽

Serum Samples ◽

Hemagglutination Assay ◽

Predictive Values ◽

Sensitivity Specificity

AbstractObjectivesTo test the performance of the newly available rapid test for syphilis, we compared it with Treponema pallidum hemagglutination assay (TPHA). Additionally, we investigated the performance of rapid plasma reagin (RPR) and chemiluminescence microparticle immunoassays (CMIA) at our laboratory using TPHA as a gold standard.MethodsThe serum samples of 595 patients with the pre-diagnosis of syphilis were studied by four serological methods. The sensitivity, specificity, and predictive values of RPR, CMIA, and syphilis rapid test were assessed by utilizing TPHA as a gold standard for the diagnosis of syphilis.ResultsOf the patients, 6.2% (37/595) had positive RPR, 5.5% (33/595) had positive CMIA, 5.5% (33/595) had a positive rapid immunochromatographic method and 5% (30/595) had positive TPHA. When TPHA results were taken as the reference, the sensitivity of the rapid test for syphilis was 100%, the specificity was 99.5%, PPV was 90.9%, and NPV was 100.0%.ConclusionsIt was observed that the rapid test for syphilis used in the study was quite successful, its cost was appropriate, and the test was very fast and easy to apply. At the same time, the agreement between syphilis rapid test and TPHA was found to be excellent.

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Diagnostic Accuracy of HRCT Chest in Detection of Covid-19 Infection Taking PCR as Gold Standard

10.53350/pjmhs211561679 ◽

2021 ◽

Vol 15 (6) ◽

pp. 1679-1681

Author(s):

Afaque Ali ◽

Majid Shaikh ◽

Ahsanullah . ◽

Adeel Ahmed ◽

Abid Ali Sahito ◽

...

Keyword(s):

Computed Tomography ◽

High Resolution ◽

Diagnostic Accuracy ◽

Predictive Value ◽

Gold Standard ◽

Cross Sectional Study ◽

Radiology Department ◽

High Resolution Computed Tomography ◽

Cross Sectional ◽

Head Of Department

Objective: To determine the diagnostic accuracy of High-resolution computed tomography (HRCT) chest in detection of covid-19 infection taking PCR as gold standard. Study Design: Cross-sectional study Setting: Radiology department of Tabba Hospital, Karachi. Duration: From March 2019 to September 2020 Material and Methods: All the clinically suspected patients of covid-19, of any age, both genders and those referred to radiology for High-resolution computed tomography (HRCT) chest to detect the covid-19 infection were included. After two days, patients’ PCR reports were collected from the ward, after taking informed consent and permission from head of department. The diagnostic accuracy of HRCT was established with respect to sensitivity, PPV, NPV, and specificity by taking PCR as gold standard. All the information was collected via study proforma. Results: Total 70 patients suspected for COVID-19 were studied, and the patients’ mean age was 58.23±9.52 years. Males were in majority 54(77.1%). As per HRCT findings, COVID-19 infection was positive in 46 patients, however, 48 patients were detected positive for COVID-19 infection as per PCR findings. In the detection of COVID-19 infection, HRCT chest showed sensitivity of 91%, specificity of 90%, PPV of 83%, NPV of 84% and diagnostic accuracy of 94%; by taking PCR as gold standard. Conclusion: High-resolution computed tomography (HRCT) is a reliable diagnostic approach in promptly detecting the COVID-19; with 91% sensitivity, 90% specificity, 83% positive predictive value, 84% negative predictive value and 94% diagnostic accuracy. Keywords: Accuracy, HRCT, COVID-19

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Evaluating Specivity, Sensitivity, Positive and Negative Predictive Values of CA125 for Diagnosing Ovarian Cancer

Journal of Arak University of Medical Sciences ◽

10.32598/jams.24.2.6002.1 ◽

2021 ◽

Vol 24 (2) ◽

pp. 196-203

Author(s):

Elahe Fini ◽

◽

Neda Nasirian ◽

Bahram Hosein Beigy ◽

◽

...

Keyword(s):

Ovarian Cancer ◽

Positive Predictive Value ◽

Tumor Marker ◽

Negative Predictive Value ◽

Predictive Value ◽

Screening Test ◽

High Sensitivity ◽

Medical Community ◽

Cross Sectional ◽

Predictive Values

Background and Aim: Ovarian cancer is among the most common cancers in women worldwide. CA125 is the most frequent biomarker used in the screening for ovarian cancer. CA125 has no high sensitivity and specificity as a screening test in the medical community; however, because of being simple and noninvasive, it is almost always requested for evaluation and ruling out cancer. It plays an important role in the treatment and post-treatment process, the prediction of prognosis, and the relapse of the disease. The present study aimed to determine the relationship between a high level of CA125 tumor marker and ovarian cancer by detecting spesivity, sensivity, positive and negative predictive values. Methods & Materials: In this cross-sectional study, all cases undergoing CA125 test in Velayat Hospital in 2017-1028 were evaluated for having ovarian cancer. In addition, the CA125 level was compared between healthy individuals and patients with ovarian cancer. Finally, the obtained data were analyzed using SPSS. Ethical Considerations: The present study was approved by the Qazvin University of Medical Sciences (Ethics Code: IR.QUMS.REC.1396.316). Results: In this study, 35.3% of the study participants received a definite diagnosis of ovarian cancer. Generally, CA125 values were negative in 41.8% and positive in.58.2% of the study subjects. The sensitivity of the test was measured as 80.1%, the specivity as 53.6%, the positive predictive value equaled 48.4%, and the negative predictive value was measured as 83%. There was a significant relationship between age and the presence of ovarian cancer, and serum CA125 levels. Conclusion: The present study suggested that age and the serum level of CA125 were statistically significant. Finally, CA125 levels were significantly related to ovarian cancer. It provided moderate specivity and specivity as well as low positive predictive value and high negative predictive value as a tumor marker; it is valuable for ruling out of tumor but not appropriate as a screening test.

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Increase in the proportion of Plasmodium falciparum with kelch13 C580Y mutation and decline in pfcrt and pfmdr1 mutant alleles in Papua New Guinea

Malaria Journal ◽

10.1186/s12936-021-03933-6 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Naoko Yoshida ◽

Masato Yamauchi ◽

Ryosuke Morikawa ◽

Francis Hombhanje ◽

Toshihiro Mita

Keyword(s):

Plasmodium Falciparum ◽

Papua New Guinea ◽

New Guinea ◽

Therapeutic Effects ◽

Cross Sectional Survey ◽

Cross Sectional ◽

In The Wild ◽

Nationwide Surveillance ◽

Greater Mekong Subregion ◽

C580y Mutation

Abstract Background The C580Y mutation in the Plasmodium falciparum kelch13 gene is the most commonly observed variant in artemisinin-resistant isolates in the Greater Mekong Subregion (GMS). Until 2017, it had not been identified outside the GMS, except for Guyana/Amazonia. In 2017, three parasites carrying the C580Y mutation were identified in Papua New Guinea (PNG). As the C580Y allele rapidly spread in the GMS, there is concern that this mutant is now spreading in PNG. Methods In 2020, a cross-sectional survey was conducted at two clinics in Wewak, PNG. Symptomatic patients infected with P. falciparum were treated with artemether plus lumefantrine following a national treatment policy. Blood samples were obtained before treatment, and polymorphisms in kelch13, pfcrt, and pfmdr1 were determined. Parasite positivity was examined on day 3. The results were compared with those of previous studies conducted in 2002, 2003, and 2016–2018. Results A total of 94 patients were included in this analysis. The proportion of C580Y was significantly increased (2.2% in 2017, 5.7% in 2018, and 6.4% in 2020; p = 4.2 × 10–3). A significant upward trend was observed in the wild-type proportion for pfcrt (1.9% in 2016 to 46.7% in 2020; p = 8.9 × 10–16) and pfmdr1 (59.5% in 2016 to 91.4% in 2020; p = 2.3 × 10–6). Among 27 patients successfully followed on day 3, including three with C580Y infections, none showed positive parasitaemia. Conclusions Under the conditions of significant increases in pfcrt K76 and pfmdr1 N86 alleles in PNG, the increase in kelch13 C580Y mutants may be a warning indicator of the emergence of parasites resistant to the currently used first-line treatment regimen of artemether plus lumefantrine. Therefore, nationwide surveillance of molecular markers for drug resistance and assessment of its therapeutic effects are important.

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Diagnostic Value of CK19, HBME-1 and TROP2 Biomarkers in Identification of Different Types of Thyroid Follicular Neoplasms

ACTA MEDICA IRANICA ◽

10.18502/acta.v59i1.5397 ◽

2021 ◽

Author(s):

Shohreh Vojuhi ◽

Masoud Mohebbi ◽

Zohreh Mousavi ◽

Mohammadali Yaghoubi ◽

Reza Ziaolhagh

Keyword(s):

Positive Predictive Value ◽

Papillary Carcinoma ◽

Predictive Value ◽

Thyroid Nodules ◽

Follicular Adenoma ◽

Thyroid Neoplasms ◽

Diagnostic Value ◽

Cross Sectional ◽

Predictive Values ◽

Different Types

Thyroid malignancies are found in 7% to 15% of all thyroid nodules. Immunohistochemical markers, including CK19, HBME-1and TROP2, have shown an effective role in identifying these malignancies. Hence, due to the lack of appropriate diagnostic tests for the identification of thyroid neoplasms, in this study, we aimed to determine the diagnostic value of these biomarkers in the identification of different types of follicular thyroid neoplasms. In this cross-sectional study, paraffin-embedded tissue blocks from the surgical resection of patients with thyroid nodules, referring to Imam Reza and Razavi Hospitals of Mashhad in 2017, were studied. Sensitivity, specificity, and positive and negative predictive values of these biomarkers for the identification of different types of follicular thyroid neoplasms were also studied. 129 patients with a mean age of 44.65±12.59 years participated in this study, of whom 101 (78.29%) were women. The most common type of follicular thyroid neoplasm was papillary carcinoma (60.47%). The highest sensitivity (94.87%) and positive predictive value (68.51%) in the detection of follicular neoplasms was observed by CK19 in papillary carcinoma. The sensitivity and positive predictive value of TROP2 in the detection of papillary neoplasms was 93.58% and 75.25%, respectively. In addition, HBME-1 had the highest specificity (72.54 %) and positive predictive value (81.57%) in identifying this neoplasm. The results of this study showed that CK19, HBME-1, and TROP2 had high diagnostic value in the detection of papillary thyroid neoplasms. Although these biomarkers had low diagnostic value in identifying follicular adenoma and carcinoma, given the high negative predictive value, they can be considered as powerful markers in identifying negative cases.

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Core Trainees' study budget and study leave: a survey exploring trainees' needs and understanding of local processes in place within the North West

BJPsych Open ◽

10.1192/bjo.2021.439 ◽

2021 ◽

Vol 7 (S1) ◽

pp. S157-S158

Author(s):

Chirag Shroff

Keyword(s):

Health Education ◽

Graphical Representation ◽

Committee Meeting ◽

Cross Sectional Survey ◽

Cross Sectional ◽

North West ◽

The North ◽

Local Board ◽

Oversight Committee ◽

New System

AimsHealth Education England launched a new system for study leave and study budget on 1st April 2018, in response to trainees' concerns regarding the previous system. According to this, Health Education England would manage the study leave budget through its local offices, making the process of accessing study ‘more transparent, equitable and streamlined' for all trainees. At the RAP Oversight Committee meeting of the North West Deanery in 2019, trainees' uncertainties over the process was discussed by the local reps. It was aimed that there was a need to gather information on trainees' needs and understanding of local processes in place by the deanery to access study leave and study budgetMethodA cross sectional survey was sent out to all the trainees by the Core Trainees year 1 RAP rep. A total of 6 relevant questions were designed and sent out to the trainees, allowing them 2 weeks’ time to respond. There were a total of 66 trainees who were sent the survey. The guidance mentioned in the 2016 Gold guide was used for reference to ensure the questions are relevant.ResultOf the total of 66 trainees who were sent the survey, there were 48 respondents. The results indicated that all 48 responders preferred study budget and leave process explained at induction. 47 of 48 respnders sought access to their study budget, 46 of 48 responders sought use of budget for external course and exam fees fudning, 27 of the 48 responders struggled to get study leave and 27 of 48 responders felt the current leave process was not satisfactory with 14 opining that there was scope for improvemement.ConclusionThe responses were collated by the trainee rep as a PowerPoint presentation containing graphical representation of trainees’ views regarding their study leaves and budget access. The survey results were made aware to the local board at the subsequent RAP Oversight Committee meeting to seek response and new guidance. There is a new system in place for study leave and study budgets, overseen by Health Education England. Overall, the survery attempted to understand and collate trainees' wants and needs, in effect improving trainee experiences.

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