Clinical feature | 2 points | 1 point | 0 point |
---|---|---|---|
Thrombocytopenia | Platelet decrease >50% from baseline platelet nadir >20,000 | Platelet decrease of 30–50% platelet nadir 10,000–19,000 | Platelet decrease <30% platelet nadir <10,000 |
Timing of platelet decrease | 5–10 days after heparin exposure OR ≤1 day (if exposed to heparin within 30 days) | Likely 5–10 days (incomplete evidence) OR onset after day 10 OR ≤1 day (if exposed to heparin within 30–100 days) | ≤4 days without recent exposure |
Thrombosis or other sequelae | New and confirmed thrombosis skin necrosis anaphylactic reaction to IV unfractionated heparin | Progressive/recurrent thrombosis non-necrotizing skin lesions unconfirmed thrombosis | None |
Other etiologies for thrombocytopenia | None | Possible | Definite |