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Test Code HITASRA Heparin Induced Thrombocytopenia (HIT) with reflex Confirmatory Testing

Specimen and Container/Tube

Specimen Type: Serum

Preferred Specimen: Red Top Tube

Other Acceptable specimens: N/A

Specimen Stability

Storage Temperature

Stability

Room temperature

8 hours

Refrigerated

72 hours

Frozen

30 days

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

NOTE: Once red top tubes are completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

NOTE: Once red top tubes are completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Collect specimen per standard collection procedure.
  • Once each red top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.
  • Specimen should be centrifuged at >2500 x g for 10 minutes.
  • Aliquot removed serum into 3 tubes containing minimum of 1.0 mL of serum each.
  • Serum samples must then be frozen at -20oC.
  • Once solidly frozen, they must be shipped on dry ice. Samples that have thawed in transit will be rejected.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.

Reference Values

 

Test

Age

Sex

Reference Range

PF4 ELISA Screen

ALL

ALL

<0.400 OD

NOTE: Positive PF4 ELISA may reflex to a confirmatory send-out Serotonin Release Assay (SRA) performed at Mayo Clinic, following interpretation and review by a coagulation pathologist. To discuss, call coagulation lab at 2-1315.

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

STAT Turnaround Time: N/A

 

Routine Turnaround Time: Up to 3 days

 

Testing Schedule: Monday to Friday.

Clinical Indications

Clinical suspicion for heparin induced thrombocytopenia. For inpatient testing only.

Test Components

HIT

CPT Codes

86022 

LOINC Codes

73818-7

Methodology

ELISA

Synonyms/Keyword Search

HITA; HIT; PF4; VITT

Additional Information

Should be ordered only in the setting of:
1) A substantial drop in the platelet count with an appropriate temporal relationship to recent heparin administration.


2) Re-exposure to heparin in patients previously diagnosed with HIT.

Last Review Date

11/10/2025

Volume

Preferred Volume: 3.0 mL serum

 

Minimum Volume: 1.5 mL serum