Heparin-induced thrombocytopenia diagnostic criteria: Difference between revisions

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===The 4T score===
===The 4T score===
The current diagnostic algorithm for HIT involves calculation of the pre-test probability using the 4T score. This scoring system is used when a patient is found to have thrombocytopenia or thrombosis after heparin exposure. It is calculated before the heparin-PF4 IgG antibody is ordered, and it offers a cost-effective and efficient way for determining the likelihood of HIT.<ref name="pmid24824208">{{cite journal| author=Gardiner EE, Andrews RK, Cuker A| title=DiagnoSTic assays for heparin-induced thrombocytopenia. | journal=Br J Haematol | year= 2014 | volume= 166 | issue= 5 | pages= 631-3 | pmid=24824208 | doi=10.1111/bjh.12940 | pmc=4134688 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24824208  }} </ref>
The current diagnostic algorithm for HIT involves calculation of the pre-test probability using the 4T score.<ref name="pmid16634744">{{cite journal| author=Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A| title=Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings. | journal=J Thromb Haemost | year= 2006 | volume= 4 | issue= 4 | pages= 759-65 | pmid=16634744 | doi=10.1111/j.1538-7836.2006.01787.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16634744  }} </ref> This scoring system is used when a patient is found to have thrombocytopenia or thrombosis after heparin exposure. It is calculated before the heparin-PF4 IgG antibody is ordered, and it offers a cost-effective and efficient way for determining the likelihood of HIT.<ref name="pmid24824208">{{cite journal| author=Gardiner EE, Andrews RK, Cuker A| title=DiagnoSTic assays for heparin-induced thrombocytopenia. | journal=Br J Haematol | year= 2014 | volume= 166 | issue= 5 | pages= 631-3 | pmid=24824208 | doi=10.1111/bjh.12940 | pmc=4134688 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24824208  }} </ref>


* '''T'''hrmobocytopenia
* '''T'''hrmobocytopenia: 2 points are assigned to platelet count fall greater than 50% and platelet nadir greater than 20,000 per microliter. 1 point is assigned to platelet count fall 30-50% or platelet nadir 10,000-19,000 per microliter. No points are assigned to platelet count fall less than 30% or platelet nadir less than 10,000 per microliter.
* '''T'''hrombosis
* '''T'''hrombosis: 2 points are assigned to new confirmed thrombosis or skin necrosis at injection sites or acute systemic reaction after IV heparin bolus. 1 point is assigned to progressive or recurrent skin lesions or suspected thrombosis (without proof of thrombosis. No points are assigned if there is no thrombosis.
* '''T'''iming
* '''T'''iming: 2 points are assigned if the platelet count fall occurs between days 5 and 10.
* o'''T'''her
* o'''T'''her


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The American Society of Hematology, as part of the [http://www.choosingwisely.org/ Choosing Wisely] program, states<ref>The American Society of Hematology. [http://www.choosingwisely.org/clinician-lists/american-society-hematology-testing-treating-suspected-heparin-induced-thrombocytopenia/Don’t test or treat for suspected heparin-induced thrombocytopenia (HIT) in patients with a low pre-test probability of HIT.]. 2014</ref>:
The American Society of Hematology, as part of the [http://www.choosingwisely.org/ Choosing Wisely] program, states<ref>The American Society of Hematology. [http://www.choosingwisely.org/clinician-lists/american-society-hematology-testing-treating-suspected-heparin-induced-thrombocytopenia/Don’t test or treat for suspected heparin-induced thrombocytopenia (HIT) in patients with a low pre-test probability of HIT.]. 2014</ref>:
: "Don’t test or treat for suspected heparin-induced thrombocytopenia (HIT) in patients with a low pre-test probability of HIT."
: "Don’t test or treat for suspected heparin-induced thrombocytopenia (HIT) in patients with a low pre-test probability of HIT."


==Reference==
==Reference==

Revision as of 04:22, 14 July 2017

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Shyam Patel [2]


Overview

Diagnostic Criteria

The 4T score

The current diagnostic algorithm for HIT involves calculation of the pre-test probability using the 4T score.[1] This scoring system is used when a patient is found to have thrombocytopenia or thrombosis after heparin exposure. It is calculated before the heparin-PF4 IgG antibody is ordered, and it offers a cost-effective and efficient way for determining the likelihood of HIT.[2]

  • Thrmobocytopenia: 2 points are assigned to platelet count fall greater than 50% and platelet nadir greater than 20,000 per microliter. 1 point is assigned to platelet count fall 30-50% or platelet nadir 10,000-19,000 per microliter. No points are assigned to platelet count fall less than 30% or platelet nadir less than 10,000 per microliter.
  • Thrombosis: 2 points are assigned to new confirmed thrombosis or skin necrosis at injection sites or acute systemic reaction after IV heparin bolus. 1 point is assigned to progressive or recurrent skin lesions or suspected thrombosis (without proof of thrombosis. No points are assigned if there is no thrombosis.
  • Timing: 2 points are assigned if the platelet count fall occurs between days 5 and 10.
  • oTher


[3]

  • 0 to 3 points: low probability
  • 4 to 5 points: intermediate probability
  • 6 to 8 points: high probability

The American Society of Hematology, as part of the Choosing Wisely program, states[4]:

"Don’t test or treat for suspected heparin-induced thrombocytopenia (HIT) in patients with a low pre-test probability of HIT."

Reference

  1. Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A (2006). "Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings". J Thromb Haemost. 4 (4): 759–65. doi:10.1111/j.1538-7836.2006.01787.x. PMID 16634744.
  2. Gardiner EE, Andrews RK, Cuker A (2014). "DiagnoSTic assays for heparin-induced thrombocytopenia". Br J Haematol. 166 (5): 631–3. doi:10.1111/bjh.12940. PMC 4134688. PMID 24824208.
  3. Cuker A, Gimotty PA, Crowther MA, Warkentin TE (2012). "Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis". Blood. 120 (20): 4160–7. doi:10.1182/blood-2012-07-443051. PMC 3501714. PMID 22990018.
  4. The American Society of Hematology. test or treat for suspected heparin-induced thrombocytopenia (HIT) in patients with a low pre-test probability of HIT.. 2014

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