🩸 4Ts Score (Heparin-Induced Thrombocytopenia)
Estimate the pre-test probability of heparin-induced thrombocytopenia with the 4Ts score.
4Ts Score (Heparin-Induced Thrombocytopenia)
Thrombocytopenia
Timing of platelet fall
Thrombosis/sequelae
Other cause of thrombocytopenia
When to use
Decide on stopping heparin and HIT testing.
How it works
0–2 points each for Thrombocytopenia, Timing, Thrombosis and oTher cause (max 8). ≤ 3 low, 4–5 intermediate, 6–8 high.
Key points
- A low score (≤ 3) has high negative predictive value.
- Intermediate/high → stop heparin, use a non-heparin anticoagulant, test.
- Confirm with anti-PF4 ELISA then a functional assay.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.