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Epic Code LAB3389 Unfractionated Heparin Level

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)

Test Name Alias

Unfractionated Heparin Blood Lvl | UFH | UF Heparin Blood Level | Unfractionated Heparin Blood Lvl | Heparin anti-xa assay | 8101

Interface Order Alias


Quick Collect


Clinical Information

Plasma unfractionated heparin (UFH) anti-Xa assay using unfractionated heparin standard curve. Assay is valid only for unfractionated heparin. The UFH anti-Xa assay should be ordered in patients when a measurement of heparin levels would be more accurate than the estimate provided by the APTT. For example, this may occur in patients with lupus anticoagulants producing an elevated baseline APTT.


In addition on October 26, 2021, the UFH level will be the test utilized to monitor heparin therapy in the pediatric patient population at HDVCH.

Collection Instructions

Specimen Collection: Blood


Container(s): 3.2% Na Citrate Tube (blue top)

Preferred Volume to Collect: 2.7 mL (full 2.7 mL blue tube)

Minimum Volume to Collect: 1.8 mL (full 1.8 mL blue white tube)

Capillary collect ok: No

Microtainer acceptable: No


Collection Instructions:


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


  • Processed Specimen: Double Spun 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 hours)

Rejection Criteria

  • Hemolysis
  • Specimen has been thawed

Specimen Stability

Ambient whole blood state unspun: 1 hour
Ambient spun: 4 hours
Frozen:  Aliquot and freeze double spun platelet poor plasma within 1 hour of collection

  • Frozen at -70°C: 2 months
  • Frozen at -20°C: 2 weeks

Test Frequency

Available daily, usual turn-around time 4 hours

Reference Range

The generally accepted therapeutic range for unfractionated heparin is 0.3 - 0.7 U/mL. This therapeutic range is used for establishing the APTT interpretive nomograms for monitoring of heparin therapy with this test.

Performing Department


Performing Department Laboratory Location

Corewell Health Reference Laboratory (SHRL), Grand Rapids, MI
Corewell Health West Hospital Labs:
Corewell Health Big Rapids Laboratory, Big Rapids, MI
Corewell Health Blodgett Laboratory, Grand Rapids, MI
Corewell Health Gerber Laboratory, Fremont, MI
Corewell Health Kelsey Laboratory, Lakeview, MI
Corewell Health Ludington Laboratory, Ludington, MI
Corewell Health Pennock Laboratory, Hastings, MI
Corewell Health Reed City Laboratory, Reed City, MI
Corewell Health Greenville Laboratory, Greenville, MI
Corewell Health Zeeland Laboratory, Zeeland, MI


Chromogenic Based Assay



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