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.<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> | 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> <ref name="pmid22990018">{{cite journal| author=Cuker A, Gimotty PA, Crowther MA, Warkentin TE| title=Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis. | journal=Blood | year= 2012 | volume= 120 | issue= 20 | pages= 4160-7 | pmid=22990018 | doi=10.1182/blood-2012-07-443051 | pmc=3501714 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22990018 }} </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: 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'''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. | ||
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* o'''T'''her: 2 points are assigned if there is no apparent alternative explanation of thrombocytopenia. 1 point is assigned if there is a possible alternative explanation of thrombocytopenia. No points are assigned if there is a definite alternative explanation of thrombocytopenia. | * o'''T'''her: 2 points are assigned if there is no apparent alternative explanation of thrombocytopenia. 1 point is assigned if there is a possible alternative explanation of thrombocytopenia. No points are assigned if there is a definite alternative explanation of thrombocytopenia. | ||
* 0 to 3 points: low probability | * 0 to 3 points: low probability | ||
Revision as of 04:30, 14 July 2017
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Heparin-induced thrombocytopenia |
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Differentiating Heparin-induced thrombocytopenia from other Diseases |
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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] [2] 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.[3]
- 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 clearly occurs between days 5 and 10, or if the platelet count fall occurs in less than 1 day if a patient had recent heparin exposure within the past 30 days. 1 point is assigned if the platelet count is likely to have fallen between days 5-10 (there may be missing platelet count checks), or platelet count fall after day 10, or platelet count fall within 1 day in the setting of prior heparin exposure 30-100 days ago. No points are assigned if platelet count fall occurs within 4 days in the setting of no heparin exposure.
- oTher: 2 points are assigned if there is no apparent alternative explanation of thrombocytopenia. 1 point is assigned if there is a possible alternative explanation of thrombocytopenia. No points are assigned if there is a definite alternative explanation of thrombocytopenia.
- 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
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 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