ARUP's Laboratory Test Directory

Heparin-Induced Thrombocytopenia (HIT) Antibodies, PF4 IgG/IgM/IgA by ELISA with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin : 0051249

Mnemonic: PLT HAT R

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Serotonin Release Assay
Performed: Sun-Sat
Reported: 1-10 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 3 mL serum to an ARUP Standard Transport Tube. (Min: 2 mL) Also acceptable: ACD or sodium citrated plasma.

Storage/Transport Temperature: CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered. Ship on dry ice.

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: Unacceptable; Frozen: 1 month
Reference Interval:
Effective November 14, 2011
 
Test Number Components Reference Interval
0051052Heparin-Induced Thrombocytopenia (HIT) Antibodies, PF4 IgG/IgM/IgA by ELISA 0.399 OD or less
2005631Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin By report

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.
Note: Positive ELISA results are relatively non-specific for a clinical diagnosis of HIT. If ELISA result is positive, then Serotonin Release Assay (a functional assay with greater specificity for a clinical diagnosis of HIT syndrome) will be added. Additional charges apply.
CPT Code(s): 86022; if reflexed add 86022
Cross References: HAT (Heparin-Induced Thrombocytopenia Antibodies with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin) , Heparin PF4 Antibody (Heparin-Induced Thrombocytopenia Antibodies with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin) , Heparin-Associated Antibody (Heparin-Induced Thrombocytopenia Antibodies with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin) , HIPA (Heparin-Induced Thrombocytopenia Antibodies with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin) , HITA (Heparin-Induced Thrombocytopenia Antibodies with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin) , Type II HIT (Heparin-Induced Thrombocytopenia Antibodies with Reflex to Serotonin Release Assay (Heparin Dependent Platelet Antibody), Unfractionated Heparin