4TS_HIT v.1
4 Ts score for heparin induced thrombocytopenia (HIT). Differentiates patients with HIT from those with other causes of thrombocytopenia.
The 4 Ts (the 4 parts of the tool starting with \"T\") score helps to stratify patients at risk of HIT (Heparin induced thrombocytopenia) among those at risk of thrombocytopen ia overall and who are taking heparin-based substances.
Those patients in the low risk group do not require further investigation for HIT. Those patients in the intermediate or high risk groups should warrant further investigation and/or changing to other anti-coagulants without heparin. There are 4 areas that are scored and each one is scored either 0,1 or 2: - Thrombocytopenia - Timing of platelet count fall - Thrombosis or other sequelae - Other causes for thrombocytopenia Interpretation: •≤3 points: low probability for HIT (≤5% in the original study). • 4-5 points: intermediate probability (~14% probability of HIT). • 6-8 points: high probability (~64% probability of HIT).
Any positive scores should lead to further clinical evidence to provide further support to the result and so the tool should not be used on its own.
Ref. 1: Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A. Evaluation of pretest clinical score (4 Ts) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings. J Thromb Haemost 2006; 4: 759–65. Ref. 2: Vatanparast R, Lantz S, Ward K, Crilley PA, Styler M. Evaluation of a pretest scoring system (4Ts) for the diagnosis of heparin-induced thrombocytopenia in a university hospital setting. Postgrad Med. 2012 Nov;124(6):36-42.
OBSERVATION.four_ts_heparin_induced_thrombocytopenia.v1, EVALUATION.four_ts_hit_assessment.v1
