Primary Name Antithrombin
Synonym Antithrombin III
Synonym Heparin cofactor activity
Contraction AT
Contraction AT III
Contraction --
UAB Procedure Number 1000760
CPT Code 85300
Specimen Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Specimen will be rejected if underfilled.

Specimen Management Centrifuge blue-stopper tube within one (1) hour of collection, separate plasma and test or quick-freeze at -70°C.
Specimen Accepted Daily including weekends
Test Performed Monday-Friday
*When the antithrombin test is ordered as part of a thrombosis risk profile, it is performed twice weekly.

Available Stat? N0.
Description When the functional AT level is consistently decreased, the patient may have a congenital deficiency. Chronic AT deficiency confers a 10- to 20-fold risk of venous thrombosis. Acquired AT deficiency occurs in prolonged heparin therapy, disseminated intravascular coagulation, surgery, preeclampsia, liver dysfunction, renal disease, and malignancies. Because the AT decreases with heparin therapy, wait 10 days after ending treatment to collect specimen.
Reference Interval 78% - 126%
Follow-up Test If the functional AT assay indicates a congenital deficiency, the antithrombin antigen assay may be used to distinguish qualitative from quantitative disorders.
Associated With Venous thrombosis
Associated With Disseminated intravascular coagulation
Associated With Liver disease

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