Validating 4Ts for Heparin Induced Thrombocytopenia (HIT)

Study Overview
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Brief Summary
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The purpose of this study is to evaluate a scoring tool to help determine the presence of Heparin Induced Thrombocytopenia (HIT), which is an adverse reaction to heparin. We hypothesize that this scoring tool will be very useful in excluding patients who are suspected of having HIT.

Detailed Description
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HIT is an immune response to heparin that can result in thrombogenic thrombocytopenia. It is often a difficult diagnosis to make, and its diagnosis is dependent upon both clinical and serologic criteria. Due to this ambiguity, increased testing and treatment may occur until serologic test results return. Recently, scoring tools have been developed to assist with the diagnosis of this disease. However, these scoring tools have yet to be validated. Thus, we plan to conduct a prospective, observational study to validate two scoring tools, the 4Ts and the Chong scale, in the diagnosis of HIT. In order to validate these scoring tools, two physicians will independently score the 4Ts and the Chong scale for all patients suspected of having HIT. These patients will be identified if a physician has ordered HIT antibody testing using the enzyme immunoassay (EIA) method. Confirmatory testing with a serotonin release assay (SRA) will also be performed.

Official Title
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Prospectively Validating the 4Ts and Chong Score for Heparin Induced Thrombocytopenia

Conditions
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Heparin-Induced Thrombocytopenia

Intervention / Treatment
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* Other: Scoring 4Ts and Chong scale
* Other: Blood draw


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with suspected HIT. Exclusion Criteria: None.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Suspected HIT<br>Those who are clinically suspected of having HIT will be enrolled in this study. | Other: Scoring 4Ts and Chong scale<br>* Two physicians will independently score both the 4Ts and the Chong scale on all patients enrolled in this study.<br>Other: Blood draw<br>* Patient serum will be collected to perform Serotonin Release Assay testing to verify the presence of HIT.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To validate the 4Ts as a pretest probability tool for HIT. |  | End of study. | 
| To validate the Chong scale as a tool to determine the post-test probability for HIT. |  | End of study. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To determine the inter-rater variability for scoring the 4Ts. |  | End of study. | 
| To determine the inter-rater variability for scoring the Chong scale. |  | End of study. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Heparin-induced thrombocytopenia, HIT, 4Ts, Chong scale, interobserver variability