Tuberculosis and Tuberculin Quality: Best Intentions, Misleading Results

2001 ◽  
Vol 22 (08) ◽  
pp. 481-484 ◽  
Author(s):  
M. Sigfrido Rangel-Frausto ◽  
Samuel Ponce-de-León-Rosales ◽  
Claudia Martinez-Abaroa ◽  
Kaare Hasløv
Keyword(s):  
Medical Students ◽  
High Risk ◽  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Healthcare Workers ◽  
Low Risk ◽  
University Hospital ◽  
High Risk Population ◽  
Risk Population

Abstract Objective: To compare the performance of three purified protein derivative (PPD) formulations: Tubersol (Connaught); RT23, Statens Serum Institut (SSI); and RT23, Mexico, tested in Mexican populations at low and high risk for tuberculosis (TB). Design: A double-blinded clinical trial. Setting: A university hospital in Mexico City. Participants: The low-risk population was first or second-year medical students with no patient contact; the high-risk population was healthcare workers at a university hospital. Methods: Each of the study subjects received the three different PPD preparations. Risk factors for TB, including age, gender, occupation, bacille Calmette-Guerin (BCG) status, and TB exposure, were recorded. A 0.1-mL aliquot of each preparation was injected in the left and right forearms of volunteers using the Mantoux technique. Blind readings were done 48 to 72 hours later. Sensitivity and specificity were calculated at 10 mm of induration using Tubersol as the reference standard. The SSI tested the potency of the different PPD preparations in previously sensitized guinea pigs. Results: The low-risk population had a prevalence of positive PPD of 26%. In the low-risk population, RT23 prepared in Mexico, compared to the 5 TU of Tubersol, had a sensitivity of 51%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 86%. The RT23 prepared at the SSI had a sensitivity of 69%, a specificity of 99%, a positive predictive value of 95%, and a negative predictive value of 90%. In the high-risk population, the prevalence of positive PPD was 57%. The RT23 prepared in Mexico had a sensitivity of 33%, a specificity of 100%, and a positive predictive value of 53%; the RT23 prepared at the SSI had a sensitivity of 91%, a specificity of 98%, a positive predictive value of 98%, and a negative predictive value of 89%. RT23 used in Mexico had a potency of only 23% of that of the control. There was no statistical association among those with a positive PPD, irrespective of previous BCG vaccination (relative risk, 0.97; 95% confidence interval, 0.76-1.3; P=.78). Conclusions: Healthcare workers had twice the prevalence of positive PPD compared to medical students. RT23 prepared in Mexico had a low sensitivity in both populations compared to 5 TU of Tubersol and RT23 prepared at the SSI. Previous BCG vaccination did not correlate with a positive PPD. Low potency of the RT23 preparation in Mexico was confirmed in guinea pigs. Best intentions in a TB program are not enough if they are not followed by high-quality control.

scholarly journals A Dispatch Screening Tool to Identify Patients at High Risk for COVID-19 in the Prehospital Setting

2021 ◽  
Vol 22 (6) ◽  
pp. 1253-1256
Author(s):  
Amy Albright ◽  
Karen Gross ◽  
Michael Hunter ◽  
Laurel O'Connor
Keyword(s):  
High Risk ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Screening Tool ◽  
Screening Tools ◽  
High Risk Population ◽  
Common Symptom ◽  
Risk Population ◽  
Positive Screen ◽  
The Impact

Introduction: Emergency medical services (EMS) dispatchers have made efforts to determine whether patients are high risk for coronavirus disease 2019 (COVID-19) so that appropriate personal protective equipment (PPE) can be donned. A screening tool is valuable as the healthcare community balances protection of medical personnel and conservation of PPE. There is little existing literature on the efficacy of prehospital COVID-19 screening tools. The objective of this study was to determine the positive and negative predictive value of an emergency infectious disease surveillance tool for detecting COVID-19 patients and the impact of positive screening on PPE usage. Methods: This study was a retrospective chart review of prehospital care reports and hospital electronic health records. We abstracted records for all 911 calls to an urban EMS from March 1–July 31, 2020 that had a documented positive screen for COVID-19 and/or had a positive COVID-19 test. The dispatch screen solicited information regarding travel, sick contacts, and high-risk symptoms. We reviewed charts to determine dispatch-screening results, the outcome of patients’ COVID-19 testing, and documentation of crew fidelity to PPE guidelines. Results: The sample size was 263. The rate of positive COVID-19 tests for all-comers in the state of Massachusetts was 2.0%. The dispatch screen had a sensitivity of 74.9% (confidence interval [CI], 69.21-80.03) and a specificity of 67.7% (CI, 66.91-68.50). The positive predictive value was 4.5% (CI, 4.17-4.80), and the negative predictive value was 99.3% (CI, 99.09-99.40). The most common symptom that triggered a positive screen was shortness of breath (51.5% of calls). The most common high-risk population identified was skilled nursing facility patients (19.5%), but most positive tests did not belong to a high-risk population (58.1%). The EMS personnel were documented as wearing full PPE for the patient in 55.7% of encounters, not wearing PPE in 8.0% of encounters, and not documented in 27.9% of encounters. Conclusion: This dispatch-screening questionnaire has a high negative predictive value but moderate sensitivity and therefore should be used with some caution to guide EMS crews in their PPE usage. Clinical judgment is still essential and may supersede screening status.

scholarly journals SARS-CoV-2 Seroprevalence in Healthcare Workers in Germany: A Follow-Up Study

2021 ◽  
Vol 18 (9) ◽  
pp. 4540
Author(s):  
Johannes Korth ◽  
Benjamin Wilde ◽  
Sebastian Dolff ◽  
Jasmin Frisch ◽  
Michael Jahn ◽  
...  
Keyword(s):  
High Risk ◽  
Healthcare Workers ◽  
Risk Group ◽  
Close Contact ◽  
Virus Transmission ◽  
High Risk Group ◽  
Low Risk ◽  
University Hospital ◽  
Intermediate Risk ◽  
Igg Antibody

SARS-CoV-2 is a worldwide challenge for the medical sector. Healthcare workers (HCW) are a cohort vulnerable to SARS-CoV-2 infection due to frequent and close contact with COVID-19 patients. However, they are also well trained and equipped with protective gear. The SARS-CoV-2 IgG antibody status was assessed at three different time points in 450 HCW of the University Hospital Essen in Germany. HCW were stratified according to contact frequencies with COVID-19 patients in (I) a high-risk group with daily contacts with known COVID-19 patients (n = 338), (II) an intermediate-risk group with daily contacts with non-COVID-19 patients (n = 78), and (III) a low-risk group without patient contacts (n = 34). The overall seroprevalence increased from 2.2% in March–May to 4.0% in June–July to 5.1% in October–December. The SARS-CoV-2 IgG detection rate was not significantly different between the high-risk group (1.8%; 3.8%; 5.5%), the intermediate-risk group (5.1%; 6.3%; 6.1%), and the low-risk group (0%, 0%, 0%). The overall SARS-CoV-2 seroprevalence remained low in HCW in western Germany one year after the outbreak of COVID-19 in Germany, and hygiene standards seemed to be effective in preventing patient-to-staff virus transmission.

Quantitative Monitoring Of Wilms’ Tumor 1 Expression In Predicting Relapse After Allogeneic Hematopoietic Stem Cell Transplantation In Patients With Acute Leukemia and Myelodysplastic Syndrome

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2075-2075
Author(s):  
Ryotaro Nakamura ◽  
Anna Israyelyan ◽  
Leanne Goldstein ◽  
Weimin Tsai ◽  
Lia Aquino ◽  
...  
Keyword(s):  
High Risk ◽  
Positive Predictive Value ◽  
Myelodysplastic Syndrome ◽  
Negative Predictive Value ◽  
Cell Transplantation ◽  
Predictive Value ◽  
Wilms Tumor ◽  
Allogeneic Hct ◽  
Qrt Pcr ◽  
High Risk Disease

Abstract Relapse is the major cause of treatment failure after allogeneic hematopoietic cell transplantation (HCT) for leukemia and myelodysplastic syndrome (MDS). In order to improve the outcome of leukemia patients after allogeneic HCT, it is imperative to identify reliable markers to predict impending relapse. Wilms’ tumor antigen (WT1) is overexpressed in the majority of leukemia and MDS patients and is being considered as a possible universal diagnostic marker for minimal residual disease (MRD), especially since no chromosomal translocation has nearly the frequency of association as WT1 does with leukemia. In this study we prospectively evaluated the prognostic value of MRD monitoring by qRT-PCR for WT1 transcripts. WT1 transcript levels in peripheral blood mononuclear cells (PBMC) were measured utilizing SYBR-Green qRT-PCR on the ABI7300 instrument (Applied Biosystems, Carlsbad, CA) and results were expressed as a ratio of WT1/c-ABL transcript copies normalized by 104 (WT1 ratio: WT1/c-ABLx104). PBMC samples were obtained monthly for 6 months post-HCT, then on alternating monthly schedule until 3 years post-HCT. Patients >18y.o. with confirmed diagnosis of MDS with <20% blasts, AML/ALL in 1st or 2ndCR, and CML in chronic phase undergoing HCT were eligible for the study. A total of 83 patients (median age: 54, range: 19-74) with AML (n=39), ALL (n=24), MDS (n=17), or CML (n=3) received allogeneic HCT after fully ablative (n=39) or reduced-intensity (n=44) conditioning. Donor sources were matched related (n=33), unrelated (n=50), or umbilical cord blood (n=2). Fifty-one patients were considered low-risk (AML/ALL in CR1, CML in 1stchronic phase, or MDS-RA/RARS subtypes) while the remaining 32 patients were considered high risk. Sixteen of 83 patients relapsed with a median time of 238 days post-HCT (range: 76-747). The minimum WT1 ratio that gave specificity of 100% in predicting relapse was 50 (95% binomial exact CI: 92.5-100%), as none of the non-relapsed patients crossed this level. Of 16 patients who relapsed, 12 crossed the WT1 ratio of 50, providing a sensitivity of 75% (95% binomial exact CI: 48- 93%). The positive predictive value (PPV) and the negative predictive value (NPV) performance parameters for the WT1 ratio of 50 were 100% and 94.4%, respectively (Table 1). There was an average number of 63 days (SD=29.3) from crossing the WT1 ratio of 50 to hematologic relapse for the 12 relapsed patients. Since PBMC samples from healthy donors consistently demonstrated a WT1 ratio <10, we also examined different WT1 cutoff ratios (10 to 50) for their performance characteristics (Table 1). Compared with the WT1 ratio of 50, a cutoff ratio at 20 resulted in an increased sensitivity (87.5%) for relapse prediction and days to relapse (78 days), while the specificity and PPV decreased to 85% and 58.3%, respectively. The performance of the cutoff ratio of 20 was improved on PPV (69%) and days to relapse (85 days) in a subgroup of patients with high-risk disease while maintaining good sensitivity and specificity above 80%. Univariate analysis showed WT1 ratios (as a continuous variable), crossing the WT1 ratio of 20 (as a time-dependent variable), high risk disease, and donor age were significantly associated with relapse. In multivariate analysis, crossing the WT1 ratio of 20 remained the only significant factor predicting relapse (HR 56.9 [18-189], p<0.0001). In summary, our data demonstrate that the quantitative measurement of WT1 transcripts is a reliable marker to assess MRD post-HCT for leukemia patients, and its real-time prospective monitoring provides a 2-3 month window of opportunity to introduce medical/immunologic interventions prior to overt hematologic relapse.Table 2WT1 ratio Specificity Sensitivity Positive Predictive Value Negative Predictive Value Days to Relapse (SD)50100%75%100%94.4%63 days (29)4095.5%75%80%94.1%66.9 days (29)3094%75%75%94%71.5 days (30)2085%87.5%58.3%96.6%78 days (28)1056.7%93.8%34.1%97.4%107.5 days (58) Disclosures: No relevant conflicts of interest to declare.

scholarly journals Prevalence of SARS-CoV-2 Antibodies in Multiple Sclerosis: The Hidden Part of the Iceberg

2020 ◽  
Vol 9 (12) ◽  
pp. 4066
Author(s):  
Nicola Capasso ◽  
Raffaele Palladino ◽  
Emma Montella ◽  
Francesca Pennino ◽  
Roberta Lanzillo ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
High Risk ◽  
Cross Sectional Study ◽  
Low Risk ◽  
High Risk Population ◽  
Chi Square ◽  
Cross Sectional ◽  
Risk Population ◽  
Exact Test ◽  
Chi Square Test

Background. We compared the prevalence of SARS-CoV-2 IgG/IgM in multiple sclerosis (MS), low-risk, and high-risk populations and explored possible clinical correlates. Methods. In this cross-sectional study, we recruited MS patients, low-risk (university staff from non-clinical departments), and high-risk individuals (healthcare staff from COVID-19 wards) from 11 May to 15 June 2020. We used lateral flow immunoassay to detect SARS-CoV-2 IgG and IgM. We used t-test, Fisher’s exact test, chi square test, or McNemar’s test, as appropriate, to evaluate between-group differences. Results. We recruited 310 MS patients (42.3 ± 12.4 years; females 67.1%), 862 low-risk individuals (42.9 ± 13.3 years; females 47.8%), and 235 high-risk individuals (39.4 ± 10.9 years; females 54.5%). The prevalence of SARS-CoV-2 IgG/IgM in MS patients (n = 9, 2.9%) was significantly lower than in the high-risk population (n = 25, 10.6%) (p < 0.001), and similar to the low-risk population (n = 11, 1.3%) (p = 0.057); these results were also confirmed after random matching by age and sex (1:1:1). No significant differences were found in demographic, clinical, treatment, and laboratory features. Among MS patients positive to SARS-CoV-2 IgG/IgM (n = 9), only two patients retrospectively reported mild and short-lasting COVID-19 symptoms. Conclusions. MS patients have similar risk of SARS-CoV-2 infection to the general population, and can be asymptomatic from COVID-19, also if using treatments with systemic immunosuppression.

scholarly journals Diagnostic accuracy of frozen section in detecting malignant brain tumors taking histopathology as gold standard.

2020 ◽  
Vol 27 (09) ◽  
pp. 1814-1817
Author(s):  
Saad Akhter Khan ◽  
Badar Uddin Ujjan ◽  
Naveed Zaman Akhunzada ◽  
Saad Bin Anis
Keyword(s):  
Positive Predictive Value ◽  
Diagnostic Accuracy ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Gold Standard ◽  
Frozen Section ◽  
Malignant Gliomas ◽  
University Hospital ◽  
Neoplastic Tissue ◽  
Tissue Water

Objectives: To evaluate the diagnostic accuracy of frozen section in detecting malignant gliomas, taking histopathology as gold standard. Study Design: Cross-Sectional study. Setting: Neurosurgery Department, Aga Khan University Hospital, Karachi. Period: From March 2018 to Jan 2019. Material & Methods: Through consecutive sampling technique, total 100 specimens from patients suspected of malignant gliomas on MRI brain with contrast, who were admitted in the neurosurgery department for elective tumor surgery were included. Intraoperatively, the specimen from the lesion identified on imaging through neuro-navigation was taken and sent to histopathology department for frozen section analysis. The histopathology consultant was pre-informed about the case and probable time of receiving the specimen. The specimen for frozen section was sent in a dried container without formalin. Once received in pathology department, the tissue is rapidly cooled through a cryostat which converts tissue water into the ice and makes the tissue rigid for cutting into slices and viewing under the microscope for identifying the neoplastic tissue. The consultant histopathologist was request to provide frozen section report immediately and to keep the remaining specimen for definitive histopathology reporting as well. Data of malignancy on both Frozen Section and formal histopathology report was noted and comparison was done. Results: Mean age of the patients was 36.7±8.76 years. There were 64 (64%) male patients and 36 (36%) female patients. Diagnostic accuracy of frozen section taking histopathology as a gold standard shows that sensitivity was found to be 83.3%, specificity 84.4%, Positive predictive value (PPV) 71.4% and negative predictive value (NPV) 91.5% & Overall diagnosis accuracy was found 96.6%. Conclusion: The Diagnostic accuracy of frozen section (FS) in detection of brain malignant gliomas was found to be satisfactory. It has a diagnostic accuracy of 96.9%, sensitivity 83.3%, specificity 84.4%, Positive predictive value (PPV) 71.4% and negative predictive value (NPV) 91.5%.

Predicting Dysphagia with National Institute of Health Stroke Scale: Distinction between Infra- and Supratentorial Region is Essential

2018 ◽  
Vol 46 (3-4) ◽  
pp. 150-158 ◽  
Author(s):  
Bendix Labeit ◽  
Hannah Mueller ◽  
Paul Muhle ◽  
Inga Claus ◽  
Tobias Warnecke ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Haemorrhagic Stroke ◽  
University Hospital ◽  
Neurogenic Dysphagia ◽  
Screening Parameter ◽  
Study Population ◽  
Moderate Sensitivity ◽  
The Ideal

Background: For the early detection of post-stroke dysphagia (PSD), valid screening parameters are crucial as part of a step-wise diagnostic procedure. This study examines the role of the National Institute of Health Stroke Scale (NIH-SS) as a potential low-threshold screening parameter. Methods: During a ten-year period, 687 newly admitted patients at University Hospital Muenster were included in a retrospective analysis, if they had ischemic or haemorrhagic stroke confirmed by neuroimaging and had received NIH-SS scoring and endoscopic swallowing evaluation upon admission. The NIH-SS score was correlated with dysphagia severity as measured by the validated 6-point fiberoptic endoscopic dysphagia severity score (FEDSS), and the ideal cut-off score to predict PSD, defined as FEDSS > 1, was calculated. Supra- and infratentorial strokes were analysed separately due to their differing role in the pathophysiology of neurogenic dysphagia. Results: NIH-SS and dysphagia severity show a significant positive correlation in the whole study population (R2 = 0.745) as well as in both analysed subgroups (R2 = 0.494 for supra- and R2 = 0.646 for infratentorial strokes, p < 0.0005, respectively). For supratentorial strokes, the ideal NIH-SS cut-off is > 9 (sensitivity 68.3%, specificity 61.5%, positive predictive value 89.7%, negative predictive value 28.4%). For infratentorial strokes, a lower ideal cut-off > 5 was calculated (sensitivity 67.4%, specificity 85.0%, positive predictive value 95.1%, negative predictive value 37.8%). Conclusions: NIH-SS may be used as an adjunct to predict dysphagia in acute stroke patients with moderate sensitivity and specificity. Differentiation between supra- and infratentorial regions is essential not to miss dysphagia in infratentorial stroke.

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