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Anti Throm III Activ (AT3A)

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EPIC Test Name

ANTITHROMBIN III ACTIVITY

EPIC Code

LAB311

Specimen Requirements

Plasma
Minimum Volume:2.7 mL
Collection:Collect using standard laboratory procedures. Tubes must be full to obtain proper blood to anticoagulant ratio or the specimen will be rejected.
Transport:Specimens scheduled to arrive in lab in less than 4 hours can be sent at room temperature. Specimens arriving more than 4 hours must be platelet poor specimens and need to be frozen before transport. Place in an insulated container filled with dry ice to ensure that the specimen does not thaw.
Stability:Room temp: 4 hours Frozen: 2 weeks at -20 C 6 months at -70 C.
Container:Light-blue top (3.2% sodium citrate)
Processing/Storage:Specimens that cannot reach the lab within the time frame should be double spun at 2500 g for 15 minutes to obtain platelet poor plasma. 0.5mL aliquots should be frozen in plastic at -20 degrees C.
Rejection Causes:Clotted
Insufficent Sample Volume

Methods

Automated chromogenic assay.

Turnaround Time

SpecimenTurnaround Time
PlasmaTesting is batched

Reference Ranges

Automated chromogenic assay.
AgeAll RangeUnit
0 day39-87 U/dLU/dL
1-5 days41-93 U/dL
5 days - 1 month48-108 U/dL
1 -3 months73-121 U/dL
3 -6 months84-124 U/dL
>6 months80-138 U/dL

Clinical Indications

To detect antithrombin deficiency. Useful in thrombophilia workup. Acquired deficiency may occur with heparin therapy and in acute venous thrombosis, consumptive coagulopathy, liver disease, L-asparaginase treatment, and nephrotic proteinuria. Antithrombin level is decreased in pregnancy.

Common Synonyms

AT III Activity, anti thrombin III

Performed

Lab
Special Testing

CPT

85300

LOINC

3174-0

Contact Information

Special Testing: (315)464-4460
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