Laboratory Services

Anti Thrombin Activity

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Updated Test Information:

Test Description
Anti Thrombin Activity
Synonym(s)

Antithrombin 3, Anti Thrombin III, Antithrombin III, UOW882

Test ID
AT3
General Information

Antithrombin (AT) exerts a powerful and immediate inhibitory action on thrombin in the presence of heparin. The Antithrombin Activity is a chromogenic assay used for diagnosing acquired or congenital antithrombin deficiency. This AT assay will detect both type I and II congenital deficiencies of Antithrombin. In addition, acquired AT deficiencies can be seen in heparin therapy, DIC, nephrotic syndrome, liver disease and L-asparaginase treatment. In some patients, AT deficiency may be associated with increased risk for venous thrombosis and insensitivity to heparin treatment.

Container Type

3mL or 5mL Blue Top (Citrate) Tube

Specimen Type

Plasma

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

1mL

Required Information

Completed Coagulation Patient Clinical History Form

Limitations

Patients on thrombin inhibitors such as hirudin (Refludan), bivalidrudin (Angiomax), Dabigatran (Pradaxa), and argatroban (Novastan) may show interference due to the direct thrombin inhibition. This may cause an over-estimation of the antithrombin concentration. This assay is not affected by therapeutic doses of heparin.

Department (code)

Coagulation

Methodology

Optical, Stago Chromogenic Antithrombin Assay

Testing Schedule

Monday, Thursday

CPT Code(s)

85300

Reference Range

Elevated antithrombin is not associated with thrombosis or bleeding.


Female/Male


Age                     Range             


 0-29d             41-125


1m-2m          48-125


3m-                   80-130 

STAT Orderable (Y/N)

No

Performing Lab

UW

LOINC Code(s)
Collection File View/Download File