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Poster Networking

Platelet Disorders

PB0697 - Quality Improvement in Testing of Heparin Induced Thrombocytopenia (QUIT HIT)

Monday, June 24, 2024
13:45 – 14:45 ICT
Room: Exhibition Hall
Background: Heparin Induced Thrombocytopenia (HIT) presents significant risks, emphasizing the need for accurate diagnosis. However, challenges emerge from improper anti-PF4 antibody testing, impacting clinical decisions.

Aims: The aim of this quality improvement study was to reduce inappropriate anti-PF4 testing by 50% over six months.

Methods: We collected data for anti-PF4 tests ordered at Singapore General Hospital. We examined the patient charts and calculated 4T scores to determine whether the requested tests were appropriate. We then used QI tools including fishbone diagram and Pareto chart to identify the top contributing causes and carried out interventions to address these. We collected data on anti-PF4 tests ordered post intervention to see if there was reduction in the inappropriate tests ordered.

Results: We found 66% of anti-PF4 tests were ordered inappropriately – defined as tests ordered when pre-test probability via 4T score was low, or no recent heparin exposure. We found the departments ordering the most were cardiovascular medicine (CVM) and cardiovascular surgery (CTVS), 38%, and renal medicine, 28%. 82% of the tests ordered by CVM/CTVS departments were deemed inappropriate. anti-PF4 antibody were routinely sent prior to left ventricular assist device (LVAD) insertion and extracorporeal membrane oxygenation (ECMO) implantation. This resulted in the change of pre-LVAD and ECMO testing guidelines to not require routine anti-PF4 testing. Post-intervention analysis showed that inappropriate anti-PF4 testing ordered by CVM/CTVS departments reduced by 61%. (Figure 1) Only 2 cases of HIT were diagnosed during this period.

Conclusion(s): Anti-PF4 antibody testing without the appropriate clinical context led to clinical challenges including anticoagulation management. The need for further specialized testing to aid in interpretation of indeterminate results is labor intensive and adds significant financial cost. With this study, we identified key contributors to inappropriate testing. Future work is planned to address rest of the factors contributing to inappropriate HIT testing.