Table 2. The 4Ts scoring system.

PLT - platelet

Source: [37]

4Ts	2 points	1 point	0 point
Thrombocytopenia	Fall > 50% & PLT nadir > 20	Fall 30-50% or PLT nadir 10-19	PLT fall < 30%
Onset of PLT count fall	Onset between 5-10 days or PLT fall < 1 d	Consistent with days 5-10 fall but not clear; onset after 10th d	PLT count fall < 4 d without recent exposure
Thrombosis or other sequelae	New thrombosis; skin necrosis	Progressive or recurrent thrombosis; skin lesions (not necrotic); not proven thrombosis	None
Other causes of thrombocytopenia	None apparent	Possible	Definite