Excluding HIT Diagnosis by a Particle Gel Immunoassay.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3405-3405
Author(s):  
Katharina Schallmoser ◽  
Camilla Drexler ◽  
Eva Rohde ◽  
Dirk Strunk ◽  
Andrea Groselj-Strele ◽  
...  
Keyword(s):  
High Titer ◽  
Rapid Test ◽  
Roc Curves ◽  
Serotonin Release ◽  
Aggregation Assay ◽  
Platelet Factor ◽  
Predictive Values ◽  
Specificity And Sensitivity ◽  
Platelet Aggregation Assay ◽  
Alternative Anticoagulation

Abstract Heparin-induced thrombocytopenia (HIT) is a prothrombotic condition, characterized by a platelet drop of >50% and/or thrombosis with a temporal relationship of 1–2 weeks after initiation of heparin treatment. These surrogate markers are useful for the clinical assessment but are hardly applicable in multi-morbid patients with clinical conditions mimicking HIT. Platelet activation assays (heparin-induced platelet aggregation assay, HIPA; serotonin release assay, SRA) and platelet factor-4/polyanion enzyme immunoassays (PF4-ELISA) confirm HIT. HIPA and SRA are highly specific but laborious requiring selected donor platelets and extended experience. High titer IgG antibodies correlate with clinical HIT, but ELISA is also time-consuming. The alternative H/PF4-antigen particle gel immunoassay (ID-PaGIA H/PF4®) is easy, provides results within one hour and detects mainly IgG, but also IgA/M antibodies. We evaluated specificity and sensitivity of the PaGIA in comparison to HIPA and ELISA (PF4-ENHANCED®) in 285 patients (median 71yrs, range 1–97, 45% cardiovascular surgery; f/m 56/73, and 55% medical, f/m 78/78) with undetermined likelihood for HIT and 89 healthy controls (median 42yrs, range 26–64, f/m 49/40) to validate it as a rapid assay to exclude HIT. HIPA was positive in 12% of patients. Based on ROC curves (ELISAs vs HIPA), OD-cutoff values for the IgG/A/M- and IgG-ELISA were 0.761 and 0.564, respectively. In controls the OD of IgG-ELISA was 0.066 (0.028–0.500) and lower than from patients’ samples negative by PaGIA and IgG/A/MELISA (n=158; 0.074; 0.009–0.339; p=0.017). PaGIA was positive in 70 patients (25%). In both patient groups both ELISA ODs were higher if PaGIA and IgG/A/MELISA were positive compared to negative PaGIA but positive IgG/A/MELISA (p<0.001; data are shown as median; range). Analyzed by ROC curves (ELISAs vs HIPA), IgG/A/MELISA (OD-cutoff 0.761) and IgG-ELISA (OD-cutoff 0.564) had sensitivities of 81% and 86%, and specificities of 75% and 81%. Positive and negative predictive values were 31% and 97% (IgG/A/MELISA) and 39% and 98% (IgG-ELISA), respectively. PaGIA, IgG/A/M- and IgG-ELISA were significant predictors for the results of HIPA (p<0.001) and the IgG-ELISA had the highest explained variance (41%). Based on our results the PaGIA may serve as a rapid test to exclude HIT since a negative PaGIA is rarely associated with high titer IgG PF4-antibodies or a positive HIPA. In cases of positive PaGIA results and in patients highly suspicious for HIT but with negative PaGIA, alternative anticoagulation should be considered until results from functional testing are available.

Effect of fondaparinux on platelet activation in the presence of heparin-dependent antibodies: a blinded comparative multicenter study with unfractionated heparin

Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 139-144 ◽  
Author(s):  
Pierre Savi ◽  
Beng H. Chong ◽  
Andreas Greinacher ◽  
Yves Gruel ◽  
John G. Kelton ◽  
...  
Keyword(s):  
Unfractionated Heparin ◽  
Factor Xa ◽  
Annexin V ◽  
Heparin Therapy ◽  
Cross Reactivity ◽  
Serotonin Release ◽  
Aggregation Assay ◽  
Platelet Factor ◽  
Platelet Aggregation Assay ◽  
History Of

Abstract Heparin-induced thrombocytopenia (HIT) is a complication of heparin therapy caused by antibodies against a complex of platelet factor 4 and heparin. Fondaparinux (Arixtra) is a new synthetic selective factor Xa inhibitor. We performed a serologic study to determine the cross-reactivity of HIT sera with fondaparinux. Using a prospective, blinded study design, 39 clinically and serologically confirmed sera from patients with HIT and 15 control sera were sent to 3 different laboratories, each of which specialized in a particular HIT assay. These include the serotonin release assay, heparin-induced platelet agglutination assay, and platelet aggregation assay. Two of 82 assays (2.4%) performed in the presence of control sera were positive, both with unfractionated heparin. In the presence of HIT sera, 75 of 94 (79.8%) evaluable assays were positive with unfractionated heparin; fondaparinux was significantly (P &lt; .001) less reactive than unfractionated heparin, only 3 of 91 evaluable assays (3.3%) being positive. Using flow cytometry, unlike unfractionated heparin, fondaparinux did not induce the binding of PAC1 and anti-CD62 monoclonal antibodies or of annexin V to platelets with HIT sera. Together, these results suggest that fondaparinux is nonreactive to HIT sera and raise the possibility that the drug may be used for prophylaxis and treatment of thrombosis in patients with a history of HIT.

scholarly journals Antibody-mediated procoagulant platelets in SARS-CoV-2- vaccination associated immune thrombotic thrombocytopenia

Haematologica ◽  
2021 ◽  
Author(s):  
Karina Althaus ◽  
Peter Möller ◽  
Günalp Uzun ◽  
Anurag Singh ◽  
Annika Beck ◽  
...  
Keyword(s):  
High Titer ◽  
Fatal Outcome ◽  
Severe Infection ◽  
Aggregation Assay ◽  
Platelet Factor ◽  
Platelet Aggregation Assay ◽  
Thrombotic Complications ◽  
Vaccination Campaigns ◽  
Immune Assays ◽  
Glomerular Capillaries

The COVID-19 pandemic has resulted in significant morbidity and mortality worldwide. To prevent severe infection, mass COVID-19 vaccination campaigns with several vaccine types are currently underway. We report pathological and immunological findings in 8 patients who developed vaccine-induced immune thrombotic thrombocytopenia (VITT) after administration of SARS-CoV-2 vaccine ChAdOx1 nCoV-19. We analyzed patient material using enzyme immune assays, flow cytometry and heparin-induced platelet aggregation assay and performed autopsies on two fatal cases. Eight patients (5 female, 3 male) with a median age of 41.5 years (range, 24 to 53) were referred to us with suspected thrombotic complications 6 to 20 days after ChAdOx1 nCoV-19 vaccination. All patients had thrombocytopenia at admission. Patients had a median platelet count of 46.5 x109/L (range, 8 to 92). Three had a fatal outcome and 5 were successfully treated. Autopsies showed arterial and venous thromboses in various organs and the occlusion of glomerular capillaries by hyaline thrombi. Sera from VITT patients contain high titer antibodies against platelet factor 4 (PF4) (OD 2.59±0.64). PF4 antibodies in VITT patients induced significant increase in procoagulant markers (P-selectin and phosphatidylserine externalization) compared to healthy volunteers and healthy vaccinated volunteers. The generation of procoagulant platelets was PF4 and heparin dependent. We demonstrate the contribution of antibody-mediated platelet activation in the pathogenesis of VITT.

scholarly journals Pediatric Appendicitis Score in differential diagnosis of acute nonspecific abdominal pain in children: age matters

2021 ◽  
pp. 22-31
Author(s):  
V.G. Vakulchyk ◽  
◽  
A.V. Kapytski ◽  
Keyword(s):  
Differential Diagnosis ◽  
Abdominal Pain ◽  
Acute Appendicitis ◽  
Roc Curves ◽  
Diagnostic Value ◽  
Diagnostic Significance ◽  
Predictive Values ◽  
Detection Frequency ◽  
Specificity And Sensitivity ◽  
Appendicitis Score

Acute nonspecific abdominal pain in children is the most common problem requiring differential diagnosis with acute appendicitis. Scales for integrated assessment of individual symptoms and their combinations have been proposed and are constantly being developed that allow predicting the likelihood of acute appendicitis. Purpose to assess diagnostic value of Pediatric Appendicitis Score (PAS) in groups of children in different ages. Materials and methods. 374 children aged 4 to 15 years with acute abdominal pain were evaluated in prospective randomized blinded study. Statistical analysis: ROC – curves, specificity and sensitivity, positive and negative predictive values; Kullback criteria; logistic regression analysis; discriminant analysis. Results. Detection frequency and diagnostic significance of the PAS scale predictors as well as obtained results by using the Pediatric Appendicitis Score depend on children age significantly. In terms of diagnosis of acute appendicitis, the PAS scale shows the best results in older children. Conclusions. Results of Pediatric Appendicitis Score depend on children ages due to different diagnostic value of predictors used in the PAS scale. Pediatric surgeons should keep in your mind these data. Modification of the scale is required taking into account the patient’s age. Further analysis of the issue of PAS using is needed. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of these Institutes. The informed consent of the patient was obtained for conducting the studies. The authors declare no conflicts of interests. Key words: acute appendicitis, children, diagnosis, PAS scale.

A New Rapid Test for the Detection of PF4:Heparin Antibodies.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3708-3708
Author(s):  
Kristi Ladvienka ◽  
Gian Paolo Visentin ◽  
Suzette Chance
Keyword(s):  
Human Serum ◽  
Method Comparison ◽  
Rapid Test ◽  
Serotonin Release ◽  
Limb Amputation ◽  
Serum Samples ◽  
Drug Induced ◽  
Platelet Factor ◽  
Functional Assays ◽  
Activation Assay

Abstract Abstract 3708 Heparin Induced Thrombocytopenia (HIT), the most frequent drug-induced immune-mediated type of thrombocytopenia, is an important and sometimes life-threatening complication of heparin therapy. HIT can be triggered by standard therapeutic dose heparin, low-dose (prophylactic treatment), low molecular weight heparin, unfractionated heparin and even by minute quantities given to flush intravascular catheters. HIT is a clinicopathologic syndrome cause by platelet activating antibodies that recognize complexes of platelet factor 4 and heparin (PF4-heparin). Thrombocytopenia occurring within 5 – 10 days of administration of heparin is the most common clinical effect. The most severe complication of HIT is the occurrence of both venous and arterial thrombosis. Venous thrombosis can result in limb gangrene and the need for limb amputation. The diagnosis of HIT is based on clinical abnormalities including thrombocytopenia with or without thrombosis and the detection of antibodies to the PF4-heparin complex (termed PF4 dependant antibodies). There are two major types of assays for the detection of heparin dependant antibodies: functional assays and PF4 dependant antigen immunoassays. Functional assays include the serotonin release assay (SRA) and the heparin induced platelet activation assay (HIPA). Enzyme linked immunoassays (ELISAs) are the most frequently used PF4 dependent antigen immunoassay. Functional assays are technically difficult to perform and are considered to be complex specialty assays. ELISAs while not complex are not generally available on a STAT basis. There is a need for a simpler assay which retains or improves the sensitivity and specificity of the existing immunoassays that can be available on a STAT basis. GTI Diagnostics is developing a rapid test based on the proprietary technology used in GTI's PF4 Enhanced® ELISA. The PF4 Rapid test is a single use, semi-quantitative assay contained in a cartridge. It is designed to detect anti-PF4-heparin antibodies in human serum and/or plasma with a total assay time of 15 minutes. The assay uses only 5 μL of human serum and/or plasma along with a proprietary antigen and a proprietary fluorescent secondary antibody used for detection. The assay results are read using a fluorescent reader. A method comparison study was conducted which included an evaluation of 83 serum samples obtained from patients receiving heparin of which 36 were positive and 22 were negative in the PF4 Enhanced® assay. These samples were also tested in the PF4 Rapid Test assay. In addition 25 samples from normal individuals who were not receiving heparin were tested in both assays. Analysis of the data using a 2×2 table (shown below) resulted in a sensitivity of 100%, a specificity of 93.6% and an overall agreement of 96.4% of the PF4 Rapid Test compared to the PF4 Enhanced®. PF4 Enhanced® ELISA Positive Negative Total PF4 Rapid Test Positive 36 3 39 Negative 0 44 44 Total 36 47 83 Although HIT is a true clinicopathological syndrome, its diagnosis still rests primarily on clinical grounds since laboratory tests may not be available locally or may not be available in a sufficiently timely manner. Owing to the high risk of thrombosis associated with HIT, antithrombotic therapy with alternative anticoagulants should be started immediately when serologic assays confirm clinical suspicion. Readily available results, obtained from immunoassays for rapid detection of antibodies against PF4-heparin complexes, may be combined with the pretest estimation of clinical probability in order to exclude and/or confirm the diagnosis of HIT; therefore, assisting physicians in the time-sensitive clinical management of HIT. Disclosures: Ladvienka: GTI Diagnostics, Inc: Employment. Visentin:GTI Diagnostics, Inc: Employment. Chance:GTI Diagnostics, Inc: Employment.

Comparative Studies on the HIT Antibody Mediated Platelet Aggregation / Serotonin Release by Synthetic Pentasaccharide and Two Chemoenzymatically Synthesized Heptasaccharides

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2231-2231
Author(s):  
Jeanine M. Walenga ◽  
Chris Aranda ◽  
Robert Linhardt ◽  
Jian Liu ◽  
Mary Lewis ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Conflicts Of Interest ◽  
Positive Control ◽  
Serotonin Release ◽  
Platelet Factor 4 ◽  
Aggregation Assay ◽  
Platelet Factor ◽  
Synthetic Oligosaccharides ◽  
Induced Aggregation

Abstract Abstract 2231 Synthetic oligosaccharides such as the Pentasaccharide (Arixtra) and its derivatives are antithrombotic agents which are clinically used in the management of thrombotic indications. These agents are claimed to be devoid of triggering the generation of HIT antibodies and therefore do not produce HIT syndrome. Several additional synthetic oligosaccharides are also developed for the management of thrombotic indications. More recently, two novel ultra low molecular weight heparins (ULMWHs) were synthesized chemoenzymatically. These ULMWHs are both heptasaccharides with AT pentasaccharide-binding sites within their structures which is comparable to the pentasaccharide. The IC50 of the anti-Xa effects of the agents are comparable to pentasaccharide, ranging from 0.7 to 1.0 ug/ml in comparison to pentasaccharide which is 0.8 ug/ml. All agents produced comparable anticoagulant effects in the Heptest clotting time. The purpose of this study is to compare the effects of the pentasaccharide and the two heptasaccharides namely ULMWH1 and ULMW2 in the HIT mediated platelet aggregation and serotonin release assays. In addition platelet factor 4 release in whole blood was also studied. The HIT mediated platelet aggregation studies were carried out utilizing a HIT antibody positive pool plasma preparation. PRP collected from 10 individual donors (250ul) was mixed with 200ul of HIT pool plasma and equilibrated at 37° C for 3 minutes. 50ul of 1, 10, and 100 ug/ml of each of these agents was added to trigger the platelet aggregation responses. Enoxaparin was used as a positive control in the same concentration ranges. The serotonin release assay was carried out using the standard method in the same concentration range monitoring the release of 14C serotonin with each of these agents. The PF4 release was also measured using an ELISA method for serotonin measurement in whole blood samples incubated with each of these agents at concentrations of 0, 10 and 100ug/ml. The pentasaccharide and the two heptasaccharides did not produce any aggregation of platelets in the HIT aggregation assay at all concentrations whereas Enoxaparin at concentrations of > 1ug/ml produces positive aggregation responses. In the 14C assay none of the agents produced any release of serotonin however Enoxaparin produced 14C release at all concentration studied. Similarly, the pentasachhardide and heptasaccharides did not produce any platelet factor 4 from the whole blood incubation studies, however Enoxaparin produced a measurable release of platelet factor 4. Interestingly, unlike Enoxaparin, the anti-Xa and heptest effects of these agents were not neutralized by platelet factor 4 or protamine sulfate. These results demonstrate that the pentasaccharide and chemoenzymatically synthesized ULMWH1 and ULMWH2 do not meditate HIT antibody induced aggregation and serotonin release. Therefore, these heptasaccharides may exhibit comparable safety profile to the pentasaccharide in heparin compromised patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals In-situ non-lethal rapid test to accurately detect the presence of the nematode parasite, Anguillicoloides crassus, in European eel, Anguilla anguilla

2020 ◽  
Author(s):  
M. De Noia ◽  
R. Poole ◽  
J. Kaufmann ◽  
C. Waters ◽  
C. Adams ◽  
...  
Keyword(s):  
Rapid Test ◽  
Anguilla Anguilla ◽  
Nematode Parasite ◽  
European Eel ◽  
In Situ Extraction ◽  
Predictive Values ◽  
Non Invasive ◽  
Specificity And Sensitivity ◽  
Anguillicoloides Crassus

AbstractAnguillicoloides crassus is an invasive nematode parasite of the European eel, Anguilla anguilla, and one of the primary drivers of eel population collapse. The presence of the parasite has been shown to impact many features of eel physiology and life history. Early detection of the parasite is vital to limit the spread of A. crassus. However, until recently, accurate diagnosis of infection could only be achieved via terminal dissection. To support A. anguilla fisheries management in the context of A. crassus we developed a rapid non-lethal and non-invasive environmental DNA method to detect the presence of the parasite in the swim bladder. Screening of 131 wild eels was undertaken between 2017 and 2019 Ireland and UK to validate the procedure. DNA extractions and PCR were conducted using both a Qiagen Stool kit at Glasgow University and in situ using Whatman qualitative filter paper No. 1 and a miniPCR DNA Discovery System™. Primers were specifically designed from the cytochrome oxidase mtDNA gene region. In situ extraction and amplification takes approx. 3h for up to 16 individuals with higher specificity and sensitivity compare to the laboratory Qiagen kit extraction. The local diagnostic procedure demonstrated Positive Predictive Values at 96% and Negative Predictive Values at 87%. Our method will be a powerful tool in the hands of fisheries managers to help protect this iconic but critically endangered species. It will allow a non-invasive monitoring of the A. crassus dispersion across the European waters.

scholarly journals Establishment and Characterization of an Empirical Biomarker SS/PV-ROC Plot Using Results of the UBC® Rapid Test in Bladder Cancer

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 729 ◽  
Author(s):  
Peter Oehr ◽  
Thorsten Ecke
Keyword(s):  
Bladder Cancer ◽  
Roc Curve ◽  
Predictive Value ◽  
Area Under The Curve ◽  
Rapid Test ◽  
Roc Curves ◽  
Threshold Value ◽  
Control Group ◽  
Predictive Values ◽  
Sensitivity Specificity

Background: This investigation included both a study of potential non-invasive diagnostic approaches for the bladder cancer biomarker UBC® Rapid Test and a study including comparative methods about sensitivity–specificity characteristic (SS-ROC) and predictive receiver operating characteristic (PV-ROC) curves that used bladder cancer as a useful example. Methods: The study included 289 urine samples from patients with tumors of the urinary bladder, patients with non-evidence of disease (NED) and healthy controls. The UBC® Rapid Test is a qualitative point of care assay. Using a photometric reader, quantitative data can also be obtained. Data for pairs of sensitivity/specificity as well as positive/negative predictive values were created by variation of threshold values for the whole patient cohort, as well as for the tumor-free control group. Based on these data, sensitivity–specificity and predictive value threshold distribution curves were constructed and transformed into SS-ROC and PV-ROC curves, which were included in a single SS/PV-ROC plot. Results: The curves revealed TPP-asymmetric improper curves which cross the diagonal from above. Evaluation of the PV-ROC curve showed that two or more distinct positive predictive values (PPV) can correspond to the same value of a negative predictive value (NPV) and vice versa, indicating a complexity in PV-ROC curves which did not exist in SS-ROC curves. In contrast to the SS-ROC curve, the PV-ROC curve had neither an area under the curve (AUC) nor a range from 0% to 100%. Sensitivity of the qualitative assay was 58.5% and specificity 88.2%, PPV was 75.6% and NPV 77.3%, at a threshold value of approximately 12.5 µg/L. Conclusions: The SS/PV-ROC plot is a new diagnostic approach which can be used for direct judgement of gain and loss of predictive values, sensitivity and specificity according to varied threshold value changes, enabling characterization, comparison and evaluation of qualitative and quantitative bioassays.

scholarly journals Novel Diagnostic Assays for Heparin-Induced Thrombocytopenia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 267-267
Author(s):  
Adam Cuker ◽  
Ann H Rux ◽  
Jillian L Hinds ◽  
May Dela Cruz ◽  
Serge Yarovoi ◽  
...  
Keyword(s):  
Laboratory Testing ◽  
Research Funding ◽  
Cell Activation ◽  
B Lymphocyte ◽  
Roc Curves ◽  
Serotonin Release ◽  
Luciferase Reporter ◽  
Advisory Committees ◽  
Platelet Factor ◽  
Heparin Induced Thrombocytopenia

Abstract Abstract 267 Introduction Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder mediated by platelet, monocyte, and endothelial cell-activating antibodies (Abs) against ultralarge complexes of platelet factor 4 (PF4) and heparin. Laboratory testing plays a key role in the diagnosis of HIT, but is associated with important shortcomings. Immunoassays such as the PF4/heparin ELISA frequently yield false-positive results due to their inability to discriminate cellular activating-Abs from their non-pathogenic counterparts. Functional assays such as the 14C-serotonin release assay (SRA) are more specific, but are unfeasible for most clinical laboratories due to the requirement for radioisotope and fresh platelets from reactive donors. KKO is a monoclonal Ab that causes a HIT-like thrombocytopenic disorder in a mouse model. Binding of KKO to immobilized PF4/heparin is inhibited by human HIT plasma, but not by plasma from patients with non-pathogenic anti-PF4/heparin Abs.1 We exploited this property of KKO to develop a KKO-inhibition (KKO-I) ELISA to detect platelet-activating Abs. We recently described a system to measure cell activation by HIT Abs: DT40 (chicken B lymphocyte) cells transfected with human FcgRIIa coupled to a luciferase reporter.2 We hypothesized that this system (DT40-luc) could be used to identify cell-activating anti-PF4/heparin Abs without need for donor platelets or radioactivity. Here we describe the KKO-I and DT40-luc assays and compare their performance to two commercially available immunoassays and the SRA in samples from 58 patients with suspected HIT and circulating anti-PF4/heparin Abs. Methods Patient samples consecutively referred to a clinical coagulation laboratory for HIT laboratory testing that tested positive by polyspecific anti-PF4/heparin ELISA were included. In addition to the polyspecific ELISA, citrated plasma samples from all patients were tested by an IgG-specific PF4/heparin ELISA, an in-house SRA, and the investigational KKO-I and DT40-luc assays. A 4Ts score to estimate the clinical likelihood of HIT was determined for each subject. The investigator performing 4Ts scoring was blinded to the results of HIT laboratory assays. Investigators performing the KKO-I and DT40-luc assays were blinded to the 4Ts score and the results of the SRA and anti-PF4/heparin ELISA. The KKO-I and DT40-luc assays were performed as previously described.1,2 HIT was defined as the combination of an intermediate or high probability 4Ts score (≥4) and a positive SRA. The performance of each assay with respect to this reference standard was evaluated by receiver-operating characteristic (ROC) analysis. Areas under the ROC curves (AUCs) were calculated and compared using the Delong method for correlated samples. Results Fifty-eight subjects were enrolled, 21 of whom met prespecified criteria for HIT. There were no significant differences in demographic characteristics between the 21 HIT-positive and 37 HIT-negative subjects. The ability of the polyspecific ELISA, IgG-specific ELISA, KKO-I, and DT40-luc assay to discriminate HIT-positive from HIT-negative subjects is shown in Figure 1. HIT-positive plasma showed significantly greater mean inhibition of KKO binding than HIT-negative plasma (70.1%, 95% CI 64.8–75.4 vs. 40.4%, 33.5–47.4, p<0.0001) (Figure 1C). Plasma from HIT-positive subjects also induced significantly greater luciferase activity (3.14, 2.25–4.03 vs. 0.96, 0.85–1.07, p<0.0001) in the DT40-luc assay (Figure 1D). ROC curves for each assay are shown in Figure 2. The AUC for KKO-I (0.92, 0.85–1.00) was significantly greater than the AUC for the polyspecific (0.82, 0.70–0.95) and IgG-specific (0.76, 0.62–0.90) ELISAs (p<0.05 for both comparisons). The AUC for DT40-luc (0.89, 0.79–0.99) was significantly greater than the AUC for the IgG-specific (p=0.046), but not the polyspecific ELISA (p=0.28). Conclusion KKO-I and DT40-luc showed better discrimination than commercially available ELISAs in a small cohort of patients with suspected HIT and anti-PF4/heparin Abs. These assays are simple to perform, do not require donor platelets or radioactivity, and hold promise for improving the specificity and feasibility of HIT laboratory testing. Further evaluation in a larger cohort of patients is required. Disclosures: Cuker: Baxter: Consultancy, Research Funding; Bayer: Consultancy; Canyon: Consultancy; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Stago: Research Funding. Arepally:Teva Pharmaceuticals: Research Funding. Cines:Amgen: Consultancy; GSK: Consultancy; Eisai: Consultancy; T2 Biosystems: Research Funding.

Platelet Coagulant Activities and Retinal Vein Thrombosis

1977 ◽  
Vol 38 (02) ◽  
pp. 0399-0406 ◽  
Author(s):  
Peter N. Walsh ◽  
Richard E. Goldberg ◽  
Richard L. Tax ◽  
Larry E. Magargal
Keyword(s):  
Platelet Aggregation ◽  
Venous Thrombosis ◽  
Retinal Vein Occlusion ◽  
Serotonin Release ◽  
Platelet Factor ◽  
Trigger Mechanism ◽  
Local Conditions ◽  
Plasma Coagulation ◽  
Vein Thrombosis ◽  
Vein Occlusion

SummaryTo determine whether platelets play a role in the pathogenesis of retinal vein occlusion (RVO), platelets and coagulation were evaluated in 28 patients with RVO. Platelet coagulant activities concerned with the initiation and early stages of intrinsic coagulation were 2–4 fold increased in 9 patients with acute primary RVO but not in patients with acute secondary (10 patients) or chronic (9 patients) RVO. Platelet factor 3 activity, platelet aggregation, serotonin release by platelets and plasma coagulation were normal in all patients. Platelets may provide a trigger mechanism for venous thrombosis in the eye when local conditions permit.

Predictive value of time-variant color-coded multiphase CT angiography (mCTA) regarding clinical outcome of acute ischemic stroke: in comparison with conventional mCTA and CT perfusion

2020 ◽  
pp. 028418512098177
Author(s):  
Yu Lin ◽  
Nannan Kang ◽  
Jianghe Kang ◽  
Shaomao Lv ◽  
Jinan Wang
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Predictive Value ◽  
Ct Perfusion ◽  
Roc Curves ◽  
Multivariate Logistic Regression Model ◽  
Infarct Core ◽  
Predictive Values ◽  
Significant Difference ◽  
Core Volume

Background Color-coded multiphase computed tomography angiography (mCTA) can provide time-variant blood flow information of collateral circulation for acute ischemic stroke (AIS). Purpose To compare the predictive values of color-coded mCTA, conventional mCTA, and CT perfusion (CTP) for the clinical outcomes of patients with AIS. Material and Methods Consecutive patients with anterior circulation AIS were retrospectively reviewed at our center. Baseline collateral scores of color-coded mCTA and conventional mCTA were assessed by a 6-point scale. The reliabilities between junior and senior observers were assessed by weighted Kappa coefficients. Receiver operating characteristic (ROC) curves and multivariate logistic regression model were applied to evaluate the predictive capabilities of color-coded mCTA and conventional mCTA scores, and CTP parameters (hypoperfusion and infarct core volume) for a favorable outcome of AIS. Results A total of 138 patients (including 70 cases of good outcomes) were included in our study. Patients with favorable prognoses were correlated with better collateral circulations on both color-coded and conventional mCTA, and smaller hypoperfusion and infarct core volume (all P < 0.05) on CTP. ROC curves revealed no significant difference between the predictive capability of color-coded and conventional mCTA ( P = 0.427). The predictive value of CTP parameters tended to be inferior to that of color-coded mCTA score (all P < 0.001). Both junior and senior observers had consistently excellent performances (κ = 0.89) when analyzing color-coded mCTA maps. Conclusion Color-coded mCTA provides prognostic information of patients with AIS equivalent to or better than that of conventional mCTA and CTP. Junior radiologists can reach high diagnostic accuracy when interpreting color-coded mCTA images.

Sign in / Sign up

Export Citation Format

Share Document