SHM Converge Scientific Abstract ePoster Gallery-Hit-or-Miss: An Elisa-Negative, Sra-Positive Case of Heparin Induced Thrombocytopenia

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This case report describes a 74-year-old woman with diabetes, hypertension, and neuropathy who presented with late anterolateral myocardial infarction complicated by cardiogenic shock from a ventricular septal rupture. During hospitalization, she developed a symptomatic right lower-extremity deep vein thrombosis, and her clinical probability for heparin-induced thrombocytopenia (HIT) was high with a 4T score of 6.<br /><br />Initial HIT testing showed a negative PF4/heparin ELISA, so heparin was restarted based on standard guideline recommendations. However, the serotonin release assay (SRA) later returned positive, confirming an uncommon but clinically important form of HIT: ELISA-negative, SRA-positive HIT. Because of this discrepancy and the patient’s strong clinical picture, hematology and vascular medicine were consulted, and she was switched back to bivalirudin. She also received perioperative plasmapheresis (PLEX) and intravenous immunoglobulin (IVIG) to allow safe heparin use during cardiopulmonary bypass for ventricular septal defect repair.<br /><br />The patient ultimately underwent successful surgery, was bridged to warfarin with bivalirudin, completed rehabilitation, and was discharged to a skilled nursing facility.<br /><br />The poster emphasizes that HIT is usually diagnosed with PF4 ELISA screening, which has a very high negative predictive value, and current guidelines support restarting heparin after a negative result. However, this case and a few prior reports show that false-negative ELISA results can occur in patients with true, platelet-activating HIT antibodies. The authors conclude that when clinical suspicion is high, additional testing or expert consultation should be pursued rather than relying on ELISA alone.

Asset Subtitle

Nickolas Steinauer

Meta Tag

Author List Allison A. Reinhardt, Bibek Saha, Charles Rohren, Katlin Schmitz, Nickolas Steinauer

Category Clinical Vignettes

Concept Heparin-Induced Thrombocytopenia

Concept Thrombocytopenia

Concept Thrombus

Concept Anti-PF4/Heparin Immunologic Testing

Concept Serotonin-Release Assay

Distinguished Non-Finalist

Presenter Organization Mayo Clinic

Presenting Author Nickolas Steinauer

Track Adult

Keywords

heparin-induced thrombocytopenia

ELISA-negative HIT

serotonin release assay

myocardial infarction

cardiogenic shock

ventricular septal rupture

deep vein thrombosis

bivalirudin

plasmapheresis

intravenous immunoglobulin

Heparin-Induced Thrombocytopenia

Thrombocytopenia

Thrombus

Anti-PF4/Heparin Immunologic Testing

Serotonin-Release Assay