Preferred Sample Type

Heparin Induced Thrombocytopenia Screen (HIT)

Heparin Induced Thrombocytopenia Screen (HIT)

Specimen Volume

6 mL Red top

Specimen Transport

Standard transport to laboratory - State for the attention of Special Coagulation on request form

Turnaround Time

21 days (Unless urgent by prior arrangement with laboratory)

Sample Processing In Laboratory

Sample should be centrifuged

Sample Stability

12 hours from venepuncture (ideally received no later than 4 hours after collection)

General Information

Note: For external requests please click Here for Coagulation Disorders request form. Please complete all information fully

Samples that meet the following criteria will not be processed:

  • Samples >12 hours old from the time of collection.
  • Samples received from other hospital laboratories that have been frozen and thawed.
  • Samples which fail the minimum data set.

Assay limitations:

  • The presence of immune complexes or other immunoglobulin aggregates in the patient sample may cause an increased non-specific binding and produce false-positives in this assay.
  • The results of this assay should not be used as the sole basis for a clinical decision.
  • Some low titre, low avidity antibodies may not be detected.
  • The PF4:PVS complexes used in this assay may differ slightly from those created by PF4:heparin. Therefore, it is possible that some antibodies could react with PVS complexes that do not react with heparin complexes and vice versa.
  • The detection of heparin-associated antibodies does not on its own confirm the diagnosis of HIT.
  • Some patients may have naturally occurring antibodies to PF4.

 

Please note samples MUST be collected into a plain red top tube. Tubes containing serum separator gel are NOT suitable.

Notes

All requests for HIT screening must be approved by a Haematology Consultant

Reference Range

Reference Ranges are dependent upon methodology:

ACUSTAR (primary method): 0-0.99 U/ml. HIT cannot be excluded for results => 1.0 U/ml

HIT ELISA (secondary method, used for VITT cases): >0.4-1.0 weak positive, >1.0 Positive

Specifications

  • EQA Status: NEQAS / ECAT
  • EQAS Scheme: Yes

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