Table 2. 4Ts Scorea
(Select only 1 option)
(continued) Score = 2 Thrombosis (or other clinical sequelae)
> Confirmed new thrombosis (venous or arterial)
> Skin necrosis at injection site
> Anaphylactoid reaction to IV heparin bolus
> Adrenal hemorrhage
Other cause for thrombocytopeniac
(Select only 1 option)
> No alternative explanation for platelet fall is evident
Possible other cause
is evident: > Sepsis without proven microbial source
Probable other cause
present: > Within 72 hours of surgery
> Thrombocytopenia associated with initiation of ventilator
> Other
> Recurrent venous thrombosis in a patient receiving therapeutic anticoagulants
> Thrombosis not suspected
> Suspected thrombosis (awaiting confirmation with imaging)
Score = 1 Score = 0
> Erythematous skin lesions at heparin injection sites
> Confirmed bacteremia/ fungemia
> Chemotherapy or radiation within past 20 days
> DIC due to non-HIT cause
> Platelet count < 20 x 109
> Non-necrotizing skin lesions at LMWH injection sites (presumed delayed- type hypersensitivity [DTH])
> Other
a Low Probability of HIT (Score 0-3) Intermediate Probability of HIT (Score 4-5) High Probability of HIT (Score 6-8)
b Timing of clinical sequelae, such as thrombocytopenia, thrombosis, or skin lesions. c Two points if necrotizing heparin-induced skin lesions even if thrombocytopenia not present. (Modified with permission from Warkentin and Linkins J Thromb Haemost 2010.)
AND given a drug implicated in causing drug-induced immune thrombocytopenia
/L
thrombocytopenic purpura
> Posttransfusion purpura > Thrombotic
