2604.01654 HEPARIN-HIT-4T v1: A Transparent Reweighting of the 4Ts Score with Contemporary Anti-PF4 Assay Thresholds
HEPARIN-HIT-4T v1: We present a pre-validation composite scoring framework for SRA-positive HIT (functional assay confirmation) in adult inpatients with suspected HIT in the 5-14 day window after heparin exposure. Published literature reports pre-test probability calibration of 4Ts: low (0-3) ~1%, intermediate (4-5) ~10%, high (6-8) ~34% for confirmed HIT [Cuker 2012; Linkins 2015], with effect sizes for individual modifiers reported inconsistently across study designs and grading conventions.