Implementation of 4T Score Documentation on PF4 Testing in Patients with Suspected Heparin-Induced Thrombocytopenia

Purpose: Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin therapy. Diagnosis requires clinical evaluation and laboratory testing. The 4T score is a pretest clinical scoring tool used to determine the probability of HIT. A non-profit health system implemented mandatory documentation of 4T score calculation prior to ordering PF4 tests for suspected HIT patients. The purpose of this performance improvement project is to evaluate the implementation of 4T score documentation on PF4 testing and argatroban utilization.

Methods: This was a retrospective, multi-site chart review of patients conducted to assess the impact of mandatory 4T score documentation prior to a PF4 order. The study included adult patients who were admitted to one of the practice sites between January 2020 and November 2022 with a suspicion of HIT and a PF4 order. The primary outcomes included the number of PF4 tests ordered and the percentage of positive PF4 results. Secondary outcomes included number of SRA orders and percentage of positive SRA results, turnaround time for SRA, and the utilization of argatroban. Data collection included baseline demographics, documentation of 4T score, PF4 results, SRA results, documentation of heparin allergy, initial anticoagulant prescribed, platelet trend, ordering provider, and duration of argatroban therapy in patients with a positive PF4 result. The analysis involved using χ2 test and Fisher's exact test for the primary outcomes.

Results: Mandatory 4T score documentation significantly reduced PF4 orders by 68% over a two-year period (p<0.0001). It also improved the percentage of positive PF4 results from 12% to 24% (p=0.60) and positive SRA results from 19% to 44% (p=0.35). Notably, after documentation of the mandatory 4T score tool, only 21% of the patients had a PF4 order placed. A total of 42 patients with a positive PF4 test were included to assess argatroban utilization. The turnaround time for SRA in these patients was 3.6 days while duration of argatroban therapy was 6.8 days.

Conclusion: Implementation of mandatory 4T score documentation significantly reduced PF4 orders and improved HIT diagnostic testing in a non-profit health system. Challenges remain with SRA turnaround time and corresponding duration of argatroban therapy. The results of this project have demonstrated that standardized documentation is essential for optimizing HIT diagnosis and management protocols. Future efforts will focus on optimizing confirmatory HIT testing and non-heparin anticoagulation therapy.