Snake envenomation: is the 20 min whole blood clotting test (WBCT20) the optimum test for management?

QJM ◽  
2019 ◽  
Vol 112 (8) ◽  
pp. 575-579 ◽  
Author(s):  
A A Dsilva ◽  
A Basheer ◽  
K Thomas
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
False Positive Rate ◽  
Clinical Signs ◽  
Snake Bite ◽  
World Health ◽  
Observer Variability ◽  
Likelihood Ratios ◽  
Inter Observer Variability ◽  
Bedside Test

Abstract Background The 20 min whole blood clotting test (WBCT20) is a simple bedside test recommended by World Health Organization (WHO) to assess hemotoxic envenomation and guide administration of polyvalent anti-snake venom (ASV). However, reliability and validity of this test has not been well documented in literature. Methods Sixty consecutive patients with history of snake bite were prospectively evaluated at a teaching hospital in India over 2 years. Envenomation was established by clinical and laboratory criteria. WBCT20 was done at 0, 4 and 12 h using standardized protocol. Prothrombin time (PT) with international normalized ratio (INR) was estimated at similar intervals to detect venom-induced consumption coagulopathy. Sensitivity, specificity and likelihood ratios (LR) were determined for WBCT20 using envenomation criteria as gold standard. WBCT20 was compared with PT/INR at cutoff values of ≥1.4 and ≥1.2. Two observers performed test–retest correlation to determine inter-observer variability of WBCT20. Results   Seventeen of 60 patients had evidence of hemotoxic envenomation. Four patients had combined neurotoxicity and hemotoxicity. Sensitivity and specificity of WBCT20 were 94 and 76%; positive and negative LR were 3.9 and 0.08, respectively. No inter-observer variability was noted. Conclusions WBCT20 is a highly sensitive test with excellent reliability for detecting envenomation. However, the false positive rate in this study was 24%. Asymptomatic snake bite patients with a positive WBCT20 but no corresponding clinical signs of envenomation should be tested using PT/INR before receiving ASV to prevent unnecessary waste of anti-venom.

6.16 Some Advances in Clinical Biochemistry Relating to Trace Metals

1983 ◽  
Vol 7 ◽  
pp. 149-150
Author(s):  
C. H. McMurray ◽  
W. J. Blanchflower ◽  
P. J. McParland ◽  
D. G. O'Neill ◽  
D. A. Rice
Keyword(s):  
Trace Metals ◽  
Blood Plasma ◽  
Whole Blood ◽  
Laboratory Tests ◽  
Blood Clotting ◽  
Clinical Biochemistry ◽  
Clinical Signs ◽  
Cu Deficiency ◽  
Phenylene Diamine

The clinical signs of copper (Cu) deficiency are largely non-specific and a number of laboratory tests have been used extensively to assist in diagnosis. Among these are whole blood, plasma and serum Cu and caeruloplasmin (McMurray, 1980). However, for any marker to be useful diagnostically, it is necessary to identify any factors which can affect it. Plasma and serum Cu are not equivalent but are related by the equation:Serum Cu (mg/l) = 11.7 + 0.66 plasma Cu (mg/l). The regression was obtained from the means of 24 groups of suckler cows and calves (> 10 animals/group). The equivalent relationship between serum and plasma caeruloplasmin is:Serum caeruloplasmin = 0.0018+ 0.59 plasma caeruloplasmin.Units of caeruloplasmin are absorbance units in the phenylene diamine assay.Thus, the range of normality will depend on the sample being used for the assay. The reduction in serum values is due to the loss of caeruloplasmin during blood clotting.

scholarly journals A Study of Significance of Poorly Differentiated Clusters in Colorectal Carcinomas: Association with Histopathological Prognostic Factors

2020 ◽  
Author(s):  
Shailja Maurya ◽  
Sapna Patel ◽  
Harish Srikantegowda
Keyword(s):  
Signet Ring Cell ◽  
World Health ◽  
P Value ◽  
Solid Cancer ◽  
Observer Variability ◽  
K Value ◽  
Inter Observer Variability ◽  
Signet Ring ◽  
Poorly Differentiated ◽  
Ring Cell

Introduction: Colorectal Cancer (CRC) is the third most common cancer worldwide with prevalence rate of 47 million per five years and 1.8 million new cases per year. Routinely differentiation-based histologic grading of CRC is used, but its clinical impact is limited by insufficient prognostic value, inter-observer variability and the difficulty of its application to specific CRC’s like mucinous, micropapillary, signet ring cell and medullary carcinomas. To overcome this, Poorly Differentiated Cluster (PDC) based grading have been proposed recently in 2012 by Ueno H et al., PDC is defined as a solid cancer cell nest comprising ≥5 cancer cells, lacking a gland-like structure. Aim: To compare PDC based grading with conventional World Health Organisation (WHO) grading in resected specimens of colorectal adenocarcinomas and to evaluate the relationship of PDC grading with known prognostic histopathological parameters. Materials and Methods: The present study was a descriptive study done duration of three years and two months in the Department of Pathology, JSS Medical College and Hospital, Mysuru, Karnataka, India. A total of 60 CRC cases were studied. WHO grading was done according to eighth edition, 2018 of the American Joint Committee on Cancer (AJCC) staging system. Haematoxylin and Eosin (H&E) stained slides were studied by two pathologists and looked for inter-observer variability by k statistics. Finally, both pathologists arrived at a consensus and was subjected for PDC grading and correlated with other prognostic histological markers. The comparison of data was done by Pearson’s Chi-square test and t-test. The p-values <0.05 were considered statistically significant. Fleiss-Cohen’s weighted k statistics was used for the assessment of inter-observer variability in tumour grading. Results: There was significant association between PDC grading and WHO grading with k-value of 0.852 and p-value of 0.001. The maximum cases on PDC grading were of G-II type-29 (48.3%) followed by G-III-25 (41.7%) and G-I-6 (10%). There was increase in G-II and G-III carcinomas, as mucinous adenocarcinoma and signet ring cell carcinomas were also graded with PDC which was not possible with current WHO grading system. Conclusion: Present study findings suggest that PDC grading is more reproducible and provides better prognostic stratification as it is less subjective than the conventional WHO grading.

scholarly journals The 20-minute whole blood clotting test (20WBCT) for snakebite coagulopathy—A systematic review and meta-analysis of diagnostic test accuracy

2021 ◽  
Vol 15 (8) ◽  
pp. e0009657
Author(s):  
Thomas Lamb ◽  
Michael Abouyannis ◽  
Sâmella Silva de Oliveira ◽  
Rachana Shenoy K. ◽  
Tulasi Geevar ◽  
...  
Keyword(s):  
Systematic Review ◽  
Whole Blood ◽  
Blood Clotting ◽  
Meta Analysis ◽  
Analysis Data ◽  
Lower Sensitivity ◽  
Test Accuracy ◽  
Inclusion Criteria ◽  
Operator Training ◽  
Bedside Test

Background The 20-minute whole blood clotting test (20WBCT) has been used to detect coagulopathy following snakebite for almost 50 years. A systematic review and meta-analysis of the 20WBCT was conducted to evaluate the accuracy of the 20WBCT to detect coagulopathy, indicative of systemic envenoming. Methods and findings Databases were searched from inception up to 09/12/2020 to identify studies that compared the 20WBCT and INR/fibrinogen on five or more subjects. Data was extracted from full-text articles by two reviewers using a predetermined form. Authors of 29 studies that lacked sufficient details in the manuscript were contacted and included if data meeting the inclusion criteria were provided. Included studies were evaluated for bias using a tailored QUADAS-2 checklist. The study protocol was prospectively registered on PROSPERO database (CRD42020168953). The searches identified 3,599 studies, 15 met the inclusion criteria and 12 were included in the meta-analysis. Data was reported from 6 countries and included a total of 2,270 patients. The aggregate weighted sensitivity of the 20WBCT at detecting INR >1.4 was 0.84 (CI 0.61 to 0.94), the specificity was 0.91 (0.76 to 0.97) and the SROC AUC was 0.94 (CI 0.91 to 0.96). The aggregate weighted sensitivity of the 20WBCT at detecting fibrinogen <100 mg/dL was 0.72 (CI 0.58 to 0.83), the specificity was 0.94 (CI 0.88 to 0.98) and the SROC AUC was 0.93 (0.91 to 0.95). Both analyses that used INR and fibrinogen as the reference test displayed considerable heterogeneity. Conclusions In the absence of laboratory clotting assays, the 20WBCT remains a highly specific and fairly sensitive bedside test at detecting coagulopathy following snakebite. However, clinicians should be aware of the importance of operator training, standardized equipment and the lower sensitivity of the 20WBCT at detecting mild coagulopathy and resolution of coagulopathy following antivenom.

scholarly journals Inter-Observer and Intra-Observer Variations in the Assessment of Epithelial Dysplasia in Oral Lichenoid Diseases

2021 ◽  
Vol 8 (2) ◽  
pp. 84-88
Author(s):  
Marwa Zohdy ◽  
Simone Cazzaniga ◽  
Helga Nievergelt ◽  
Roland Blum ◽  
Valérie G. A. Suter ◽  
...  
Keyword(s):  
Lichen Planus ◽  
Oral Lichen Planus ◽  
Epithelial Dysplasia ◽  
Observer Variability ◽  
Oral Lichenoid Lesions ◽  
Inter Observer Variability ◽  
Oral Lichen

Oral lichen planus (OLP) and oral lichenoid lesions (OLL) can both present with histological dysplasia. Despite the presence of WHO-defined criteria for the evaluation of epithelial dysplasia, its assessment is frequently subjective (inter-observer variability). The lack of reproducibility in the evaluation of dysplasia is even more complex in the presence of a lichenoid inflammation. We evaluated dysplasia in 112 oral biopsies with lichenoid inflammation in order to study the inter-observer and the intra-observer variability.

scholarly journals Automated left atrial time-resolved segmentation in MRI long-axis cine images using active contours

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ricardo A. Gonzales ◽  
Felicia Seemann ◽  
Jérôme Lamy ◽  
Per M. Arvidsson ◽  
Einar Heiberg ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Active Contours ◽  
Imaging Biomarkers ◽  
Observer Variability ◽  
Time Resolved ◽  
Variability Analysis ◽  
Automated Method ◽  
Inter Observer Variability ◽  
Atrial Size ◽  
And Function

Abstract Background Segmentation of the left atrium (LA) is required to evaluate atrial size and function, which are important imaging biomarkers for a wide range of cardiovascular conditions, such as atrial fibrillation, stroke, and diastolic dysfunction. LA segmentations are currently being performed manually, which is time-consuming and observer-dependent. Methods This study presents an automated image processing algorithm for time-resolved LA segmentation in cardiac magnetic resonance imaging (MRI) long-axis cine images of the 2-chamber (2ch) and 4-chamber (4ch) views using active contours. The proposed algorithm combines mitral valve tracking, automated threshold calculation, edge detection on a radially resampled image, edge tracking based on Dijkstra’s algorithm, and post-processing involving smoothing and interpolation. The algorithm was evaluated in 37 patients diagnosed mainly with paroxysmal atrial fibrillation. Segmentation accuracy was assessed using the Dice similarity coefficient (DSC) and Hausdorff distance (HD), with manual segmentations in all time frames as the reference standard. For inter-observer variability analysis, a second observer performed manual segmentations at end-diastole and end-systole on all subjects. Results The proposed automated method achieved high performance in segmenting the LA in long-axis cine sequences, with a DSC of 0.96 for 2ch and 0.95 for 4ch, and an HD of 5.5 mm for 2ch and 6.4 mm for 4ch. The manual inter-observer variability analysis had an average DSC of 0.95 and an average HD of 4.9 mm. Conclusion The proposed automated method achieved performance on par with human experts analyzing MRI images for evaluation of atrial size and function.

scholarly journals Assessment of intramyocardial hemorrhage with dark-blood T2*-weighted cardiovascular magnetic resonance

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Xingmin Guan ◽  
Yinyin Chen ◽  
Hsin-Jung Yang ◽  
Xinheng Zhang ◽  
Daoyuan Ren ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Major Adverse Cardiovascular Events ◽  
Observer Variability ◽  
Dark Blood ◽  
Imaging Characteristics ◽  
Inter Observer Variability ◽  
Sensitivity Specificity ◽  
Bright Blood ◽  
T2 Weighted Images

Abstract Background Intramyocardial hemorrhage (IMH) within myocardial infarction (MI) is associated with major adverse cardiovascular events. Bright-blood T2*-based cardiovascular magnetic resonance (CMR) has emerged as the reference standard for non-invasive IMH detection. Despite this, the dark-blood T2*-based CMR is becoming interchangeably used with bright-blood T2*-weighted CMR in both clinical and preclinical settings for IMH detection. To date however, the relative merits of dark-blood T2*-weighted with respect to bright-blood T2*-weighted CMR for IMH characterization has not been studied. We investigated the diagnostic capacity of dark-blood T2*-weighted CMR against bright-blood T2*-weighted CMR for IMH characterization in clinical and preclinical settings. Materials and methods Hemorrhagic MI patients (n = 20) and canines (n = 11) were imaged in the acute and chronic phases at 1.5 and 3 T with dark- and bright-blood T2*-weighted CMR. Imaging characteristics (Relative signal-to-noise (SNR), Relative contrast-to-noise (CNR), IMH Extent) and diagnostic performance (sensitivity, specificity, accuracy, area-under-the-curve, and inter-observer variability) of dark-blood T2*-weighted CMR for IMH characterization were assessed relative to bright-blood T2*-weighted CMR. Results At both clinical and preclinical settings, compared to bright-blood T2*-weighted CMR, dark-blood T2*-weighted images had significantly lower SNR, CNR and reduced IMH extent (all p < 0.05). Dark-blood T2*-weighted CMR also demonstrated weaker sensitivity, specificity, accuracy, and inter-observer variability compared to bright-blood T2*-weighted CMR (all p < 0.05). These observations were consistent across infarct age and imaging field strengths. Conclusion While IMH can be visible on dark-blood T2*-weighted CMR, the overall conspicuity of IMH is significantly reduced compared to that observed in bright-blood T2*-weighted images, across infarct age in clinical and preclinical settings at 1.5 and 3 T. Hence, bright-blood T2*-weighted CMR would be preferable for clinical use since dark-blood T2*-weighted CMR carries the potential to misclassify hemorrhagic MIs as non-hemorrhagic MIs.

The Haemocompatibility of Biomaterials In Vitro: Investigations on the Mechanism of the Whole-blood Clot Formation Test

1992 ◽  
Vol 20 (3) ◽  
pp. 390-395 ◽  
Author(s):  
Thomas Groth ◽  
Katrin Derdau ◽  
Frank Strietzel ◽  
Frank Foerster ◽  
Hartmut Wolf
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Blood Clot ◽  
Formation Rate ◽  
Clot Formation ◽  
Coagulation Cascade ◽  
Contact Activation ◽  
Human Fibrinogen ◽  
Static Conditions

Twenty years ago Imai & Nose introduced a whole-blood clotting test for the estimation of haemocompatibility of biomaterials in vitro In our paper a modification of this assay is described and the mechanism of clot formation further elucidated. It was found that neither the inhibition of platelet function nor the removal of platelets from blood significantly changed the clot formation rate on glass and polyvinyl chloride in comparison to the rate tor whole blood. Scanning electron microscopy demonstrated that platelets were not involved in clot formation near the blood/biomaterial interface. Thus, it was concluded that the system of contact activation of the coagulation cascade dominates during clot formation under static conditions. The latter conclusion was supported by the fact that preadsorption of human serum albumin or human fibrinogen onto the glass plates used, decreased the clot formation rate in the same manner.

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