Objectives: The American Society of Hematology's 4T scoring system is a validated tool to assess a patient's probability of having heparin-induced thrombocytopenia (HIT) before testing is performed. There is no benefit to testing patients with a low probability 4T score for HIT. This study aimed to assess for inappropriate HIT testing at our institution based on 4T scoring. Methods:We retrospectively reviewed 201 patient charts and calculated 4T scores and testing costs to assess for inappropriate testing and the economic impact of such testing.Results: HIT testing often occurred in the least appropriate patients and resulted in tens of thousands of dollars of waste for unnecessary testing.Conclusions: Inappropriate testing for HIT is still a prevalent issue despite literature supporting the 4T score for guidance in testing appropriateness.