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Epic Code LAB3377 APTT Heparin Neutralization

Important Note

There is currently a nationwide shortage of this tube. Please take steps to ensure specimen integrity to reduce recollection. Specimen Tube Shortage (link)

Specimen tube must be full. The ratio of blood to anticoagulant is critical. Increased or decreased volumes of anticoagulant will cause erroneous results.

Test Name Alias

Activated Partial Thromboplastin Time (APTT) | APTT Heparin Neutralization

Interface Order Alias


Clinical Information

For use as a heparin neutralizer in plasma to rule out heparin contamination in coagulation testing.

Panel Information


Heparin Neutralized PTT

Collection Instructions

Specimen Collection: Blood


Container(s): 3.2% Na. Citrate (blue tube)

Preferred Volume to Collect: 2.7 mL (full tube)

Minimum Volume to Collect: 1.8 mL (full tube)

Capillary collect ok: No

Microtainer acceptable: No


Collection Instructions:

  • Detailed instructions (link): Anticoagulant Correction for High Hematocrit

  • Detailed collection instructions (link): Blue Citrate Tube

  • Specimen should be processed within 4 hours – See Processing Instructions.

    • Specimen collected from patients receiving heparin therapy must be centrifuged within 1 hour --See Processing Instructions 

Processing Instructions (Laboratory, Outpatient or Off-site collection)

Processed Specimen: Platelet Poor Plasma


Centrifuge/Spin: Yes

Aliquot: Yes


Processing Instructions:

  • Detailed instructions (link): Preparing Platelet Poor Plasma
  • Separate plasma into 2 - 3 aliquots, minimum of 0.5 mL each.
  • Freeze aliquots in plastic transport tubes immediately.

Transport Temperature:

  • Ambient (Up to 1 hour in whole blood state)
  • Frozen (Plasma Only >1 hour post collection)

Rejection Criteria

  • Hemolysis
  • Specimen has been thawed

Specimen Stability

Ambient: 1 hour in whole blood state

Refrigerate: not acceptable

Frozen: Plasma only > 1 hour post collection

Laboratory Retention: 24 hours

Test Frequency

Available 24 hours, usual TAT 1 day.

Reference Range

Effective 9/26/2023 at 9:00 AM

  • 24-34 seconds (Corewell Health Reference Lab, Grand Rapids, CS 5100 Analyzer)

  • 23-28 seconds (Corewell Health Reference Lab, Grand Rapids, BCS XP analyzer)

Performing Department


Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI


Heparinase cleaves heparin at multiple sites per molecule.  Hepzyme can neutralize up to 2 USP units of unfractionated heparin in 1 mL of citrated plasma.



CDM Code


Epic Test ID




Mayo Access Code


Reviewed Date


Last Update

9/26/2023, 09:07: Reference Range