Enforcing the "4T": An In-Line Calculator for HIT Antibody Ordering in the Electronic Medical Record

Heparin-induced thrombocytopenia (HIT) remains a difficult clinical diagnosis, even with the under-utilized standardized scoring systems, like the '4T' score, to aid in clinical decision-making. Our quality improvement study sought to assess the use of '4T' score, improve the use of HIT antibody (HITA) testing and improvement management of possible HIT by implementing an in-line calculator with guidance within our electronic medical record (EMR) at our institution. We retrospectively reviewed patient charts between October 2017 and October 2018, assessing practices before and after implementation of the '4T' in-line calculator in April 2018. HITA were ordered inappropriately (for 4T <4) in 141 (67%) of 210 instances (75 before and 66 after). We found no statistically significant difference in positive predictive value (PPV) or 4T documentation in provider notes after its implementation. We were able to identify problematic areas in HIT management, such as the ordering of non-heparin anticoagulants, and implement additional changes addressing these problems.