Heparin-Induced Thrombocytopenia (HIT) Antibodies, PF4 IgG/IgM/IgA by ELISA (INACTIVE as of 10/05/15: Refer to August 2015 Hot Line Test 2012179)
Ordering Recommendation
Use for initial screening test for HIT. Confirmation with SRA (2005631) may be necessary depending on clinical presentation.
Semi-Quantitative Enzyme-Linked Immunosorbent Assay
1-2 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
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.  
Unacceptable Conditions
Heparinized specimens.  
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  
Microbially contaminated, heat-inactivated, hemolyzed, icteric, or lipemic sera may give inconsistent results.
CPT Code(s)
Component Test Code*Component Chart NameLOINC
0051052Heparin-Induced Thrombocytopenia Abs PF434701-3
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • HAT
  • Heparin Induced Antibodies
  • Heparin PF4 Antibody
  • Heparin-Asscociated Antibody
  • HIPA
  • HIT Antibodies
  • HIT IgG, IgM, IgA
  • HIT PF4 Antibodies
  • HITA
  • Type II HIT