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Specimen Collection Manual and Test Catalog

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HEPARIN PLATELET FACTOR 4 IGG ANTIBODY WITH REFLEX TO SEROTONIN RELEASE ASSAY

Geisinger Epic Procedure Code:  LAB2428    Geisinger Epic ID:  46467

SPECIMEN COLLECTION
Specimen type: 

Serum


Preferred collection container: 
Alternate collection container: 
6 mL red-top (plain, non-serum separator) tube
Specimen required: 

1.5 mL aliquot serum; minimum 0.8 mL. Please submit a separate aliquot for the HITREF. It may not be combined with any other test.



SPECIMEN PROCESSING
Processing instructions: 

Allow serum to clot. Centrifuge and submit 1.5 ml aliquot of serum for HITREF in its own tube.


Transport temperature: 

Refrigerated.


Specimen stability: 

Room temperature: 8 hours for HITGAM. Refrigerated (HITGAM orSERREL ): 48 hours. Frozen: 6 months. Do not send frozen unless two aliquots are submitted.


Rejection criteria: 

Stability limits exceeded or grossly hemolyzed.



TEST DETAILS
Reference interval: 

HITGAM <0.400; SERREL reference ranges and interpretation will accompany report.


Additional information: 

HITGAM performed at GMC. If positive, SERREL sent to Quest reference laboratory.


CPT code(s):  86022 x 2
Note: The billing party has sole responsibility for CPT coding.  Any questions regarding coding should be directed to the payer being billed.
The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only.

Test includes: 

HITGAM Polyspecific (IGG, IGA, IGM) antibody to platelet factor 4 with reflex to Serotonin Release Assay if positive.


Methodology: 
Enzyme-Linked Immunosorbent Assay (ELISA)
Radio Binding 14C Serotonin Radiolabel
Synonyms: 

Anti-platelet factor 4, Anti-PF4 HAT, Heparin-induced thrombocytopenia GAM Heparin-associated antibody (HITGAM), SERREL: Serotonin Release Assay (SRA) Quest test code 14627, HITREF


Clinical significance: 

Heparin-induced thrombocytopenia (HIT) is the most common form of drug-induced thrombocytopenia and can develop in up to 5% of patients treated with heparin. A presumptive diagnosis of HIT can be based on a > 50% reduction in platelet count more than 5 days after initiation of heparin therapy, a platelet count <150,000/uL or the development of thromboembolic complications


Doctoral Director(s): 
Benjamin Andress, PhD, DABCC
Hoi-Ying Elsie Yu, PhD, DABCC, FADLM
Review Date:  02/11/2025

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