Heparin-Induced Thrombocytopenia (HIT) PF4 Antibody, IgG

Casandra

Casandra Test Code AR32723Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2012179CPT Code 86022

Heparin-Induced Thrombocytopenia (HIT) PF4 Antibody, IgG

Also known as: HIT IGG

Clinical Use

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Use

This test is used for initial screening of heparin-PF4 antibodies that cause Heparin-Induced Thrombocytopenia (HIT). Most cases of HIT are due to IgG antibodies against heparin-PF4 complexes. The assay has a good negative predictive value for HIT, meaning that a negative result can usually rule out HIT. However, positive results, while sensitive for HIT, are not completely specific, indicating that other clinical factors and test results should be considered. Higher optical densities in the IgG ELISA test correlate with a higher likelihood of a positive result in platelet activation assays and an increased likelihood of clinical HIT.

Special Instructions

This test may need confirmation with the Serotonin Release Assay (SRA), particularly in the presence of certain clinical presentations. Avoid using heparinized specimens as they are unacceptable for this assay.

Limitations

The test detects IgG antibodies and does not detect IgA or IgM antibodies which may occasionally be associated with HIT. False negatives are rare, but possible. The test alone is not diagnostic and must be considered in conjunction with clinical findings and other laboratory tests. The presence of microbially contaminated, heat-inactivated, hemolyzed, icteric, or lipemic serum specimens may lead to inconsistent results.

Test Details

New York Approved