Antithrombin (AT) Antigen (Immunologic)
Use
Confirmation and characterization of congenital AT deficiency
Special Instructions
If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions. Blood should be collected in a blue-top sodium citrate tube, filled completely to ensure proper blood-to-anticoagulant ratio, and mixed immediately by gentle inversion.
Limitations
AT testing should not be performed on patients on heparin therapy because heparin decreases plasma AT levels. Results for individuals on warfarin therapy should be interpreted with caution as warfarin can elevate AT levels to the normal range in those with heterozygous deficiency. This test was developed by Labcorp and has not been FDA approved.
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 27812-7
- 27812-7
Result Turnaround Time
2-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
2 mL
Minimum Volume
1 mL
Container
Blue-top (sodium citrate) tube
Collection Instructions
Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated tubes must be filled to completion and mixed immediately by gentle inversion at least six times. A discard tube is not required unless collected using a butterfly collection system.
Patient Preparation
Do not draw from an arm with a heparin lock or heparinized catheter.
Storage Instructions
Freeze.
Causes for Rejection
Severe hemolysis; improper labeling; clotted specimen; specimen diluted with IV fluids; samples thawed in transit; improper sample type; sample out of stability
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 28 days |