ARUP's Laboratory Test Directory

Heparin-Induced Thrombocytopenia (HIT) Antibodies, PF4 IgG/IgM/IgA by ELISA : 0051052

Mnemonic: PLT HAT

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Performed: Sun-Sat
Reported: 1-2 days
Specimen Required: Collect: Plain red or serum separator tube (SST).

Specimen Preparation: Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to ARUP Standard Transport Tube. (Min: 0.2 mL) Also acceptable: ACD or sodium citrated plasma.

Storage/Transport Temperature: CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered. Specimen may be stored refrigerated if tested within 48 hours.
Pediatric Transport: Ship on dry ice using overnight service.

Remarks: Microbially contaminated, heat-inactivated, hemolyzed, icteric, or lipemic sera may give inconsistent results.

Unacceptable Conditions: Heparinized specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: Unacceptable; Refrigerated: 48 hours; Frozen: 1 month
Reference Interval:
0.399 OD or less
Interpretive Data: By itself, a positive result on this ELISA test is relatively non-specific for a clinical diagnosis of heparin-associated antibody syndrome (HIT) (frequent false-positives) and a negative result does not exclude a diagnosis of HIT if the clinical suspicion remains high (occasional false-negatives). Results should be used in conjunction with clinical findings, platelet counts and other laboratory results.

For a clinical scoring system to assess pretest probability of HIT and other guidance for diagnosing HIT, refer to the Heparin-Associated Antibody Syndrome topic at arupconsult.com.
CPT Code(s): 86022
Cross References: HAT (Heparin-Induced Thrombocytopenia Antibodies), Heparin PF4 Antibody (Heparin-Induced Thrombocytopenia Antibodies), Heparin-Asscociated Antibody (Heparin-Induced Thrombocytopenia Antibodies), HIPA (Heparin-Induced Thrombocytopenia Antibodies), HITA (Heparin-Induced Thrombocytopenia Antibodies), Type II HIT (Heparin-Induced Thrombocytopenia Antibodies)