Assess pre-test probability of Heparin-Induced Thrombocytopenia.
4Ts Score—
Pre-test Probability—
Recommendation—
4Ts Scoring:
0-3: Low probability (~5% risk of HIT)
4-5: Intermediate (~14% risk)
6-8: High probability (~64% risk)
About the 4Ts Score
The 4Ts score evaluates four criteria — Thrombocytopenia, Timing, Thrombosis, and oTher causes — to estimate the likelihood of HIT. A low score can safely rule out HIT, while intermediate and high scores warrant further testing with immunoassays and functional assays.