Antithrombin (AT) Deficiency Profile
Use
Confirmation and characterization of congenital AT deficiency
Special Instructions
If patient's hematocrit exceeds 55%, adjust the volume of citrate in the collection tube. Refer to Coagulation Collection Procedures for direction. Do not draw from an arm with a heparin lock or catheter. Patients should ideally not be on unfractionated heparin or direct Xa inhibitor therapy.
Limitations
Testing should not be performed on patients on heparin therapy due to decreased plasma AT levels. Results for individuals on warfarin therapy should be interpreted with caution, as warfarin can increase AT levels into the normal range. Thrombin inhibitors like dabigatran, hirudin, and argatroban interfere with the AT activity assay when based on thrombin inhibition. Direct Xa anticoagulants will interfere with assays based on Xa inhibition, causing results to be falsely elevated.
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
LOINC Codes
- 27811-9
- 27812-7
Result Turnaround Time
2-3 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
Not provided
Container
Blue-top (sodium citrate) tube
Collection Instructions
Citrate plasma samples should be collected by double centrifugation. Use a plastic transfer pipette to carefully remove 2/3 of the plasma, avoiding cells. Freeze immediately and maintain frozen until testing.
Patient Preparation
Do not draw from an arm with a heparin lock or catheter. Patients should not be on unfractionated heparin or direct Xa inhibitor therapy.
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