Background: Heparin-induced thrombocytopenia (HIT) is an acquired prothrombotic state from anti-heparin platelet-factor 4 (PF4) mediated activation of platelets. Anti-PF4 assay is used to screen for HIT due to high sensitivity and negative predictive value. Case Report: We present a 74-year-old male that had clinical HIT with false negative anti-PF4 and subsequently positive serotonin release assay (SRA). Delay in cessation of heparin led to recurrent limb thrombosis in the setting of multiple revascularization attempts with a poor outcome. Conclusion: We re-emphasize the importance of clinical presentation in management of patients with suspected HIT.
LaMuragliaGMHoubballahRLaposataM. The identification and management of heparin-induced thrombocytopenia in the vascular patient. J Vasc Surg. 2012;55:562-570.
2.
MartelNLeeJWellsPS. Risk for heparin-induced thrombocytopenia with unfractionated and low-molecular-weight heparin thromboprophylaxis: a meta-analysis. Blood. 2005;106:2710-2715.
3.
WarkentinTELevineMNHirshJ, et al.Heparin-induced thrombocytopenia in patients treated with low-molecular-weight heparin or unfractionated heparin. N Engl J Med. 1995;332:1330-1336.
4.
GreinacherAFarnerBKrollHKohlmannTWarkentinTEEichlerP, Clinical features of heparin-induced thrombocytopenia including risk factors for thrombosis. A retrospective analysis of 408 patients. Thromb Haemost. 2005;94:132-135.
5.
SahuKKJindalVAndersonJSiddiquiADJaiyesimiIA, Current perspectives on diagnostic assays and Anti-PF4 antibodies for the diagnosis of heparin-induced thrombocytopenia. J Blood Med. 2020;11:267.
SheridanDCarterCKeltonJG. A diagnostic test for heparin-induced thrombocytopenia. Blood. 1986;67:27-30.
8.
PatelRVargaC. Heparin-induced thrombocytopenia in a cardiac surgery patient with early and persistent thrombocytopenia and initial negative immunological and functional assays. Thromb Res. 2018;169:93-95.
9.
OmerTMullaguriNGeorgePNeweyCR, False-negative platelet factor 4 antibodies and serotonin release assay and the utility of repeat testing in the diagnosis of heparin-induced thrombocytopenia and thrombosis. Case Rep Hematol. 2019;2019:1-4.
10.
NicolasDNicolasSHodgensA, et al.Heparin-Induced Thrombocytopenia. Springer; 2020.
