PF4
HIT

Heparin Induced Platelet Antibody

Heparin Induced Platelet Antibody

Evaluation of possible immune-mediated type II heparin-induced thrombocytopenia (HIT-II) which should be suspected for the following patients: -Patients not previously exposed to heparin, the development of absolute thrombocytopenia or decrease in platelet count of ≥50% from baseline or postoperative peak with the onset of thrombocytopenia beginning approximately 5 to 10 days after initiation of heparin. This may or may not be associated with new or progressive thrombosis in patients treated with heparin. -Patients previously exposed to heparin (especially within the preceding 100 days), in addition to the above findings, the onset of thrombocytopenia could occur within 24 to 48 hours after reexposure to heparin. In patients with prior suspected or documented heparin-induced thrombocytopenia (HIT), with or without thrombosis, assay for presence of human platelet factor 4 (H/PF4) antibody may be useful in assessment of the risk of recurrence of HIT with additional exposure to heparin, however, prospective data are limited.  

Blood

Blue Top Tube

Container/Tube:  Light Blue Citrated tube Specimen:  0.5-1.0 mL platelet poor citrated plasma Transport Temperature:  Refrigerate or Frozen   Collection Instructions: 1. If the light blue top tube is the only tube to be drawn and will be collected using a butterfly set, a “discard” tube (either a plain[non-additive] or light blue) must be partially drawn just to completely fill the collection tubing with blood before collecting the light blue top for testing.  2. Allow blood to fill the tube completely to the line on the tube.  The ratio of blood to anticoagulant is critical in coagulation testing and at least a 90% fill is required. 3. Immediately mix the specimen by gently inverting the tube 4-6 times to completely mix with the anticoagulant.  Failure to perform this can result in a clotted sample, which is unacceptable for testing.       4. If centrifugation of the specimen cannot be performed immediately after collection, whole blood can be kept in the blue top tube at room temperature (18-24° C) for up to 4 hours.  5. If centrifugation is possible, and transport to the lab will not occur within 1 hour, spin down, remove the plasma to a clean plastic transport tube using a plastic transfer pipette, and spin the plasma again. Remove the plasma with a clean plastic transfer pipette to a fresh transport container and freeze this citrated platelet-poor plasma immediately.  A double centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.   6. Each coagulation assay requested should have its own vial of citrated plasma,1.0mL each.  

Refrigerate or Frozen

Latex Immunoturbidimetric Asssay

Monday through Sunday TAT - 2 hrs

Northwell Health Laboratories

86022   LOINC Code:  57761-9

5700180