Antithrombin Antigen, Plasma
Use
The Antithrombin Antigen test is used to assess abnormal results of the antithrombin activity assay and is recommended as a primary screening test. It is crucial for diagnosing antithrombin deficiency, whether acquired or congenital, in conjunction with measuring antithrombin activity. The test is also an adjunct in the diagnosis and management of carbohydrate-deficient glycoprotein syndromes. Antithrombin plays a key role as a plasma anticoagulant by inactivating serine protease procoagulant enzymes like thrombin and coagulation factors Xa and IXa, with its activity markedly enhanced by heparin and other naturally occurring glycosaminoglycans.
Special Instructions
Not provided.
Limitations
Antithrombin antigen results can be affected by high levels of heparin, hemoglobin, bilirubin, lipemia, and rheumatoid factor, leading to either an underestimation or overestimation of antithrombin levels. Moreover, contamination with platelets in the plasma can result in inaccurate measurements.
New York Approved
Methodology
Immunoassay (Latex Immunoassay)
Biomarkers
Antithrombin
Protein
LOINC Codes
- 27812-7 - AT III Ag Act/Nor PPP IA
- 27812-7 - AT III Ag Act/Nor PPP IA
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
Polypropylene plastic vial (after centrifugation)
Collection Instructions
Collect in a light-blue top tube (3.2% sodium citrate). Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of the centrifuged vial. Freeze plasma immediately at -20 degrees C or ideally at -40 degrees C or below.
Patient Preparation
Fasting: 8 hours, preferred but not required
Causes for Rejection
Gross hemolysis, Gross lipemia, Gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |