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Test Code AT3 AG Antithrombin III Antigen Level  

Clinical System Name

Antithrombin III Antigen Level

Synonyms

Anti Thrombin III Antigen
Anti-Thrombin III Antigen
AT III Ag
AT3 AG 

Description

 Antithrombin III (AT3) antigen is a potent inhibitor of thrombin, and in the presence of heparin, inhibition of thrombin is increased at least 1000-fold. Loss of AT3 activity can be due to congenital defects, liver failure or partial removal, active thrombotic disease, and extended administration of heparin over the course of several days.

Sample Requirements

Specimen: Whole Blood

Container(s): Lt. Blue /Citrate

Preferred Vol :1.8 mL tube

Minimum Vol: N

 

Note: Preferred method of collection is venipuncture with vacuum fill.  Test results are affected by incorrect blood volume.  Use of a Vascular Access Device for the  collection of coag testing is not recommended.

If this method is used it requires a 5 cc clearing volume; 3 cc for size 2 French catheter or smaller. Blood must be trasferred to the  Lt Blue/Citrate tube by use of a  blood transfer device to ensure proper fill. 

Specimen should be centrifuged within 1 hour of collection.

Processing Instructions

 

Reject due to: Clotted, Hemolyzed, Insufficient quantity, and  Improper collection.

Spin: N

Aliquot: N

Temp: RT

Storage location: Core 6 Freezer  ( -70 C).

 

Note: Deliver blood to Core Coag bench.  Coag Technologist will process. Specimen should be centrifuged within 1 hour of collection. Spin whole blood, remove plasma. Transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label.

 

 

Off-site collection: Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume. Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used it requires a 5 cc clearing volume; 3 cc for size 2 French catheter or smaller. Blood must be transferred to the Lt Blue/Citrate tube by use of the blood transfer device.

Specimen should be centrifuged within 1 hour of collection. Double spin, transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label. Freeze one aliquot of 1.0 mL plasma in plastic tube at -70C.

Ship frozen on dry ice.

Stability

Specimen Type Temperature Time
Citrated platelet-poor plasma Room temp N
  Refrigerated N
  Frozen   -20C or -70 3 m

 

Availability

STAT Performed TAT
Y Daily 1 h

 

Performing Laboratory

Seattle Children's Laboratory    

 

Department

Department:  Coagulation

Phone Number: 206 987-2578

 

 

 

Reference Range

 

Age %
0 - 1 month 41 - 125
1 mo - 3 mo 48 - 125
3 mo - adult 75 - 125

 

Methodology

Method:  Latex Agglutination using  the immuno-turbidimetric determination by STA® Compact  Analyzers

Analytical Volume: 0.5 mL  plasma

 

Limitations:  Results affected by moderate lipemia, moderate hemolysis, and moderate icterus.

Method is affected by improper collection, processing and storage.

High hematocrit greater than or equal to 56% requires a citrate adjusted tube.

CPT Codes

 85301