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

7 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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