Validating 4Ts for Heparin Induced Thrombocytopenia (HIT)

The recruitment status of this study is unknown because the information has not been verified recently.
Verified July 2009 by Washington Hospital Center.
Recruitment status was  Not yet recruiting
Information provided by:
Washington Hospital Center Identifier:
First received: July 24, 2009
Last updated: NA
Last verified: July 2009
History: No changes posted
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.

Condition Intervention
Heparin-Induced Thrombocytopenia
Other: Scoring 4Ts and Chong scale
Other: Blood draw

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Prospectively Validating the 4Ts and Chong Score for Heparin Induced Thrombocytopenia

Resource links provided by NLM:

Further study details as provided by Washington Hospital Center:

Primary Outcome Measures:
  • To validate the 4Ts as a pretest probability tool for HIT. [ Time Frame: End of study. ] [ Designated as safety issue: No ]
  • To validate the Chong scale as a tool to determine the post-test probability for HIT. [ Time Frame: End of study. ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • To determine the inter-rater variability for scoring the 4Ts. [ Time Frame: End of study. ] [ Designated as safety issue: No ]
  • To determine the inter-rater variability for scoring the Chong scale. [ Time Frame: End of study. ] [ Designated as safety issue: No ]

Biospecimen Retention:   Samples Without DNA
Serum will be collected to perform a serotonin release assay as confirmatory testing for the presence of HIT.

Estimated Enrollment: 500
Study Start Date: August 2009
Groups/Cohorts Assigned Interventions
Suspected HIT
Those who are clinically suspected of having HIT will be enrolled in this study.
Other: Scoring 4Ts and Chong scale
Two physicians will independently score both the 4Ts and the Chong scale on all patients enrolled in this study.
Other: Blood draw
Patient serum will be collected to perform Serotonin Release Assay testing to verify the presence of HIT.

Detailed Description:

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.


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
For this study, patients already admitted to the hospital whose physician suspects the presence of HIT will be recruited for this study. Specifically, the trigger for recruitment include patients who have a HIT antibody test ordered.

Inclusion Criteria:

  • Patients with suspected HIT.

Exclusion Criteria:

  Contacts and Locations
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Please refer to this study by its identifier: NCT00946400

Contact: Chee M Chan, MD (202) 877-7856

United States, District of Columbia
Washington Hospital Center Not yet recruiting
Washington, District of Columbia, United States, 20010
Sub-Investigator: Andrew F Shorr, MD, MPH         
Sub-Investigator: Christian Woods, MD         
Sponsors and Collaborators
Washington Hospital Center
Principal Investigator: Chee M Chan, MD Washington Hospital Center
Study Director: Andrew F Shorr, MD, MPH Washington Hospital Center
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: George Sciortino, Medstar Research Institute Identifier: NCT00946400     History of Changes
Other Study ID Numbers: 2009-202 
Study First Received: July 24, 2009
Last Updated: July 24, 2009
Health Authority: United States: Institutional Review Board

Keywords provided by Washington Hospital Center:
Heparin-induced thrombocytopenia
Chong scale
interobserver variability

Additional relevant MeSH terms:
Blood Platelet Disorders
Bone Marrow Diseases
Hematologic Diseases
Myeloproliferative Disorders processed this record on May 24, 2016