Days Set Up
Tuesday
Analytic Time

1 hour

MiChart Code
Antithrombin III
Soft Order Code
AT3

Test Updated:

Synonyms

Antithrombin III Assay, Functional
Serine Protease Inhibitor
AT3
ANTITHROMBIN III ACTIVITY
Factor 10a Inhibition

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Test Overview

Test Methodology

Chromogenic

Test Usage

AT3 levels are used as a possible indicator of hypercoagulability, and to test for the hereditary deficiency of antithrombin. AT3 levels might also be of use in cases of suspected heparin failure especially prior to heparinization.

Reference Range

75 - 125%

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

Collect specimen in a blue top (citrate 3.2%) tube. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.

Collection Offsite

Collect specimen in a blue top (citrate 3.2%) tube. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, aliquot plasma into a plastic vial, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.

Blue Top Tube
Normal Volume
Full 2.7mL tube or 1 mL plasma aliquot
Minimum Volume
Full 1.8mL tube or 1 mL plasma aliquot

Billing Information

CPT Code
85300
Pro Fee Code
 
LOINC
 

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.