Antithrombin III (Functional/Immunologic)

Test ID: 


CPT code:

85300, 85301

Clinical Use:

Confirmation and characterization of congenital AT deficiency

Test Information:

Antithrombin (AT), often referred to as antithrombin III, is a glycoprotein produced in the liver.7-9 AT is a serine protease inhibitor, or SERPIN, that irreversibly inhibits several of the enzymes involved in hemostasis. In this way, AT serves an important role in controlling coagulation by limiting the extent of thrombus formation

Specimen Type:

Plasma, frozen

Requested Volume: 

3 mL

Minimum Volume: 

2 mL

Container Type: 

Blue-top (sodium citrate) tube

Patient Prep.

Do not draw from an arm with a heparin lock or heparinized catheter.


Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood

Storage Instructions:


Stability Requirements:

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days

Rejection Criteria

Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability

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MCI Diagnostic

Providing top patient care with fast results. 

7018 South Utica Avenue

Tulsa, Oklahoma 74136

Hours of Operation

Mon – Sat: 7AM-11PM

Sun: 7AM-3PM

Government Contract

Mon – Sat: 7AM-11PM

Sun: 7AM-3PM


Mon – Sat: 7AM-11PM

Sun: 7AM-3PM

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