ARUP's Laboratory Test Directory

0051052: Heparin-Induced Thrombocytopenia Antibodies

Test Mnemonic: PLT HAT
Methodology: Enzyme-Linked Immunosorbent Assay

Performed: Sun-Sat

Reported: 1-2 days

Specimen Required:  
Collect: One 7 mL plain red.

Transport: 1 mL serum, frozen.  (Min: 0.2 mL) Also acceptable: plasma (EDTA or sodium citrate).  Submit specimen in an ARUP Standard Transport Tube.

Pediatric Collection/Transport: 0.2 mL serum, frozen.  Ship on dry ice using overnight service.

Remarks: CRITICAL FROZEN.  Separate specimens must be submitted when multiple tests are ordered.  Remove serum or plasma from cells ASAP.  Specimen may be stored at 2-8°C if tested within 48 hours.

Unacceptable Conditions: Heparinized specimens.  Microbially contaminated, hemolyzed, icteric, lipemic, or heat-inactivated sera may give inconsistent results. 

Stability: After separation from cells: Ambient: Unacceptable; Refrigerated: 2 days; Frozen: 1 month

Reference Interval:
0.399 OD or less

Interpretive Data:
An enzyme-linked immunosorbent assay (ELISA) method is used for the detection of heparin-associated antibodies.  Results obtained using this assay should be used in conjunction with clinical findings or other serological tests.

Patients receiving heparin treatment for at least a week often develop thrombocytopenia.  Two types of heparin-induced thrombocytopenia (HIT), Type I & II, may develop.  Type I HIT is generally considered a benign condition and is not antibody-mediated.  In Type II HIT, thrombocytopenia is usually more severe and is antibody-mediated.  Patients with Type II HIT are at risk to develop more severe thrombocytopenia as well as arterial or venous thrombosis if heparin therapy is continued.  Antibodies associated with HIT bind to complexes of heparin and platelet factor 4 (PF4).  These immune complexes propagate platelet activation, leading to release of more PF4 and thrombosis.



CPT Code(s):
86022

 

 

 
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