A Case of Hyperacute Severe Thrombocytopenia Occurring Less than 24 Hours after Intravenous Tirofiban Infusion
Table 2
The 4Ts score is the sum of the values for each of the 4 categories.
The 4Ts scoring system
4Ts category
2 points
1 point
0 points
Thrombocytopenia
Platelet count fall >50% and platelet nadir ≥20
Platelet count 30%–50% or platelet nadir 10–19
Platelet count fall <30% or platelet nadir <10
Timing of platelet count fall
Clear onset days 5–10 or platelet fall ≤1 day (prior heparin exposure within 30 days)
Consistent with days 5–10 fall, but not clear (e.g., missing platelet counts); onset after day 10; or fall ≤1 day (prior heparin exposure 30–100 days ago)
