HEPARIN NEUTRALIZATION: (000-0000)

 Rule out heparin contamination as the reason for abnormal coagulation results on PT and aPTT.

 HEPNEUT

 Platelet-poor plasma is added to a vial of Hepzyme (Heparinase is specific for heparin, and cleaves the  heparin molecule producing oligosaccharides that have lost their thrombotic activity), and allowed to sit at room temp for 15 minutes. The plasma is then tested for PT and/or aPTT. Hepzyme can neutralize up to 2 USP units of unfractionated heparin in 1 ml of citrated plasma. If heparin level in plasma is greater than 2 USP units, but less than 4 USP units, sequential neutralization may be performed.

 Accepted 24 hours/day at Sample Management, Room 5.136 McCullough.

 STAT: 1 hour; ROUTINE: 4 hours

Collect: Routine venipuncture; discard 1st mL of blood or collect other tubes (EDTA, red-topped) prior to collecting sample in blue-topped (3.2% sodium-citrate) tube.

Specimen Preparation: Samples should be received in laboratory within ½ hour of draw for best results.  Acceptable up to 4 hours after draw, at ROOM TEMPERATURE.

Storage/Transport: NOTE: If delivery time is to be greater than 4 hours from time of draw, centrifuge the sample, separate the plasma from the cells and snap freeze (-20⁰C) the plasma.

Stability: Snap frozen plasma is viable for 6 months.

Causes for Rejection: QNS, clotted, severely hemolyzed specimen, specimen greater than 4 hours old, wrong tube (3.8% sodium citrate), high hematocrit (> 55%), identification error, sample processed/transported, and/or stored improperly.

Patient result will have the following comment: “Heparin neutralization performed”

Limitations:  In evaluating Hepzyme results of patients during heparin therapy, the presence of TFPI (Tissue Factor Pathway Inhibitor) should be considered.  The levels of TFPI increase several fold following heparin injection.  An increase in TFPI activity has been associated with an anticoagulant effect that is not removed by heparin neutralization and may result in prolonged clotting times.  For patients receiving oral anticoagulants, thrombolytic therapy, or patients with circulating inhibitors or anti-phospholipid antibodies, the medication and clinical histories should be considered when interpreting results.  These patients may have underlying conditions that result in prolongation of the APTT and/or PT in the absence of heparin. Thrombin Times should not be performed on samples that have been sequentially neutralized.

Differences in test values before and after plasma treatment with Hepzyme indicates the presence of heparin in the sample. Hepzyme will neutralize heparin that may have contaminated the sample, and . in-vivo heparin from patients on heparin therapy. Therefore, a heparin neutralization should not be done on patient’s whose heparin therapy is being monitored with the aPTT. See “Collection and Handling of Coagulation Specimens” for instructions on how to avoid heparin contamination.

 85525

When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient.  Components of the organ or disease panels may be ordered individually.  The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-9 code or its verbal equivalent.

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