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Heparin PF4 antibody (HIT)
Lab code: HITG
Test Synonyms:
Heparin induced thrombocytopenia; HIT; PF4 antibody
Inpatient Req:
Coagulation (#70130)  
Outpatient Req:
Coagulation (#70130)  
Blue 3 ml
Result Time:
1 day   Cost: $
Reference Interval:
Important Information:
The Heparin-PF4 ELISA for heparin-induced thrombocytopenia (HIT) detects IgG HIT antibodies. It is NOT useful as a screening test (meaning, it should generally only be sent when HIT is suspected). Under usual clinical care it should only be ordered for patients with: (a) Platelets <150,000 and/or >=40% drop from baseline (b) New thrombotic event on heparin or (c) Inflammatory or necrotic lesions at injection sites of heparin. Note: Patients with a prior exposure for whom heparin therapy is under consideration may be considered for the heparin-PF4 ELISA test to determine continued presence of antibody. (Note: The antibody gradually disappears after heparin discontinuation, and therefore a negative test after heparin discontinuation does not necessarily exclude previous HIT). Available once daily: specimens must be received by Special Coagulation Lab (tube station 41) by 12:30 pm M-F or 10:00 am on weekends.