Heparin-Induced Thrombocytopenia With a False Negative Anti-PF4 Assay

Area of Science:

• Hematology
• Immunology
• Clinical Medicine

Background:

• Heparin-induced thrombocytopenia (HIT) is a prothrombotic condition.
• It arises from antibodies targeting heparin-platelet factor 4 complexes.
• Anti-heparin platelet-factor 4 assays are commonly used for HIT screening.

Purpose of the Study:

• To highlight the importance of clinical presentation in HIT diagnosis.
• To report a case of HIT with discordant assay results.
• To emphasize timely heparin cessation in suspected HIT.

Main Methods:

• Case report of a 74-year-old male with suspected HIT.
• Utilized anti-heparin platelet-factor 4 assay and serotonin release assay (SRA).
• Clinical assessment of thrombosis and response to heparin cessation.

Main Results:

• The patient presented with clinical HIT but initially had a false negative anti-PF4 assay.
• Subsequent serotonin release assay (SRA) confirmed HIT.
• Delayed heparin cessation resulted in recurrent limb thrombosis and poor outcomes.

Conclusions:

• Clinical suspicion of HIT must guide management, even with initial negative laboratory findings.
• Serotonin release assay (SRA) can be crucial when anti-PF4 assays are discordant.
• Prompt recognition and management of HIT are vital to prevent severe thrombotic complications.