Heparin Anti Xa Assay




Test Mnemonic

HEPASY

CPT Codes

  • 85520 - QTY (1)

LOINC ®

3217-7

Aliases

  • Factor Xa Inhibition/Heparin Assay
  • Heparin Assay

Includes

  • Heparin Anti Xa

Performing Laboratory

Cleveland Clinic Laboratories


Specimen Requirements

Volume Type Container Collect Temperature Transport Temperature Special Instructions
Volume1 mLTypePlatelet-poor plasmaContainerSodium citrate (Lt. Blue)Collect Temperature Transport TemperatureCentrifuge, aliquot and freeze ASAP.Special InstructionsCollection tube must be filled to total fill volume. Inadequately filled tubes will be rejected. Non Testing Sites: Centrifuge within one hour of collection, aliquot platelet poor plasma into a separate tube with Epic Beaker label, freeze plasma at -20C, send frozen plasma to Main Campus on dry ice.
Volume1.8 mLTypeWhole bloodContainerSodium citrate (Lt. Blue)Collect TemperatureAmbientTransport TemperatureCentrifuge, aliquot and freeze ASAP.Special InstructionsCollection tube must be filled to total fill volume. Inadequately filled tubes will be rejected. Non Testing Sites: Centrifuge within one hour of collection, aliquot platelet poor plasma into a separate tube with Epic Beaker label, freeze plasma at -20C, send frozen plasma to Main Campus on dry ice.

Stability

Environmental Condition Description
Environmental ConditionAmbientDescriptionCentrifuge within one hour of phlebotomy and test or freeze platelet poor plasma within four hours.
Environmental ConditionFrozenDescription3 days at less than or equal to -18 degrees C (platelet poor plasma) 3 months at less than or equal to -74 degrees C (platelet poor plasma)
Environmental ConditionRefrigeratedDescriptionUnacceptable

Days Performed

Sun - Sat

Turnaround Time

4 hours

Methodology

Name Description
NameChromogenicDescription 

Reference Range

Heparin Anti Xa
Sex Age From Age To Type Range Range Unit
Heparin Anti Xa Sex  YearsAge From99 YearsAge ToNormalTypeTherapeutic range: 0.3 - 0.7 (standard nomogram)RangeIU/mL
Heparin Anti Xa Sex  YearsAge From99 YearsAge ToNormalType< 0.10RangeIU/mL
Heparin Anti Xa Sex  YearsAge From99 YearsAge ToNormalTypeStroke or low dose protocol: 0.2 - 0.5 (see EPIC for detailed nomogram)RangeIU/mL

Special Info

3.2% sodium citrate is the preferred anticoagulant recommended by CLSI. Patient samples should be centrifuged by the laboratory < 1 hour from collection time to prevent falsely decreased Heparin Anti Xa values due to heparin neutralization by in vitro release of platelet factor 4. Samples that are centrifuged > 1 and < 4 hours from collection will have the following comment attached: Interpret with caution. Sample centrifuged greater than 1 hour from collection time. According to Clinical and Laboratory Standards Institute guidelines, results could be falsely decreased due to heparin neutralization by in vitro release of platelet factor 4. Suggest correlation with clinical findings and redraw if indicated.

Clinical Info

For monitoring unfractionated heparin therapy. This assay may be useful in monitoring heparin therapy in individuals where the APTT cannot be used due to basal APTT elevation, such as those with a lupus anticoagulant.