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Antithrombin Antigen Level

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Updated Test Information:

Test Description
Antithrombin Antigen Level
Synonym(s)

Anti thrombin, AT, AT3, Heparin Cofactor, UOW4749
Test ID
ATAG
General Information

Patients on heparin therapy may see decreased antithrombin concentrations.
If there is a concern for heparin resistance, order Antithrombin Antigen (ATAG) instead of Antithrombin Activity (AT3). If evaluating Antithrombin for hypercoagulability, recommend ordering Antithrombin Activity assay [code: AT3].
Container Type

One full 3 or 5 mL Blue Top (Citrate) tube
Specimen Type

Blood
Specimen Requirements

Whole Tube
Specimen Collection / Processing Instructions

MUST PROCESS WITHIN 4 HOURS OF COLLECTION
Platelet poor Coag Citrate Specimen processing:
1. Gently invert tube 2-3 times prior to placing in Centrifuge            
2. Centrifuge Citrate whole blood at 4500 rpm for 10 minutes
3. Carefully pipette plasma, avoiding the platelet/buffy coat into a plastic vial
4. Centrifuge plasma at 4500 rpm for 10 minutes
5. Pipette the plasma to a plastic vial, leaving the bottom 0.25 mL undisturbed
6. Freeze plasma immediately and transport frozen. 
Minimum Sample Volume

0.5 mL plasma
Stability

Frozen. Transport on dry ice.
Department (code)

Coagulation (COAG)
Methodology

Immunoturbidimetric
Estimated TAT

1 day
Testing Schedule

Daily
CPT Code(s)

85301
Reference Range

80-120


Units: %


Effective date: 05/02/2016
Performing Lab

UW
LOINC Code(s)