Antithrombin Assay
Test Mnemonic
AT3ASY
CPT Codes
- 85300 - QTY (1)
LOINC ®
27811-9
Aliases
- AT Assay
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 2 mL | Plasma | Sodium citrate (Lt. Blue) | Frozen |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 4 hours |
| Refrigerated | Unacceptable |
| Frozen | 14 days at -20 C; 6 months at -70 C |
Days Performed
Mon - Fri
Turnaround Time
1 - 3 days
Methodology
| Name | Description |
|---|---|
| Chromogenic |
Special Info
3.2% sodium citrate is the preferred anticoagulant recommended by CLSI. Formerly called Antithrombin III Assay.
Clinical Info
(1) Evaluation of the hypercoagulable state to detect congenital and acquired antithrombin deficiency.(2) Useful in diagnosing disseminated intravascular coagulation.(3) Following the response to therapy with antithrombin concentrates.(4) Evaluation of heparin resistance. Patients with antithrombin levels < 65% may have an inadequate clinical response to heparin. Heparin therapy decreases levels to a variable degree.