Home
HelpTest Code LAB311 Antithrombin III Activity Level
Clinical System Name
Antithrombin III Activity Level
Synonyms
LAB311
AT3 ACT
A THRMBIN3
Anti Thrombin III Activity
Anti-Thrombin III
AT III Activity
AT3 ACT
Sample Requirements
Specimen: Whole Blood
Container(s): Lt. Blue/Citrate
Required Vol: one 1.8 mL tube or one 2.7 mL tube (do NOT over or under fill)
Minimum Vol: N
Note: Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volume, note fill line on tube.
Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used, it requires a 5 mL waste volume, 3 mL for size 2 French catheter or smaller. Blood must be transferred 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
Main Campus CPA: Core Technologist will process specimen. Deliver blood directly to Core Coag bench.
Reject due to: Clotted, Insufficient quantity (underfill), or Improper collection (overfill).
Spin: Y
Aliquot: Y
Storage location: Core 14 Freezer ( -70 C).
Core Technologist: 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, note the fill line on the tube. Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used it requires a 5 mL waste volume; 3 mL 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 until solid one aliquot of 1.0 mL plasma in plastic tube at -70C (preferred) or -20C.
Non-Children's Hospital Off-site collection: Ship completely frozen on dry ice.
Children's Regional Clinics: Ship completely frozen in frozen Nalgene Labtop cooler with ice pack inside an insulated soft cooler.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Citrated platelet-poor plasma | Room temp |
≤ 4 h |
| Refrigerated | No | |
| Frozen -20 C or -70 C |
≤ 1 m |
Availability
| STAT | Performed | TAT |
|---|---|---|
| Y | Daily | 1 h |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Coagulation
Phone Number: 206 987-2617 (Client Services)
CPT Codes
85300
Methodology
Method: Chromogenic Substrate by STA-R MAX
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.
Reference Range
| Age | % |
| 0 - 1 m | 41 - 125 |
| 1 m - 3 m | 48 - 125 |
| 3 m - adult | 75 - 125 |
Description
For the quantitative determination of the antithrombin activity level in plasma. The test procedure is not affected by therapeutic doses of heparin. It is therefore suitable for testing of plasmas collected from patients receiving heparin therapy.