Sign in →

Test Code AT3B Antithrombin Activity

Specimen and Container/Tube

Specimen Type: Plasma

Preferred Specimen: Light Blue Top Tube, 3.2% Sodium Citrate

Other Acceptable specimens: N/A

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately. 

 

NOTE: Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Collect specimen per standard collection procedure.
  • Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Carefully remove plasma from cells using a plastic transfer pipette avoiding buffy coat.
  • Aliquot removed plasma into 2 plastic tubes containing a minimum of 0.5 mL of specimen in each tube.
  • Plasma samples must then be frozen at -20oC.
  • Once solidly frozen, they must be shipped on dry ice. Samples that have thawed in transit will be rejected.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that have wrong ratio of blood to anticoagulant (fill volume), clotted or grossly hemolyzed.

Reference Values

 

Test

Age

Sex

Reference Range

Anti-thrombin

All

All

80 - 138 %

Critical Values

Analyte

Unit

Low

High

Age

N/A

N/A

N/A

N/A

N/A

CPT Codes

85300 

LOINC Codes

27811-9

Volume

Preferred Volume: 1.0 mL

 

Minimum Volume: 0.5 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

4 hours

Refrigerated

not acceptable

Frozen

30 days

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

NOTE: Once each blue top tube is completely filled, gently invert the sample tube at least five times to ensure complete mixing of the contents.

 

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

STAT Turnaround Time: N/A

 

Routine Turnaround Time: up to 72 hours

 

Testing Schedule: Monday to Friday, first shift only (8 am to 3:30 pm).

Clinical Indications

Measuring functional level of Antithrombin.

 

Investigating congential thrombophilia or acquired AT deficiency as seen in heparinized patients (particularly pediatric ECMO patients)

Methodology

Chromogenic

Synonyms/Keyword Search

AT; AT3; Antithrombin 3, Antithrombin III

Additional Information

Direct thrombin inhibitors such as dabigatran and argatrobancause an overestimation (false increase) of the antithrombin level.

 

All 3.2% sodium citrate light blue top tubes must have 9 to 1 ratio of blood to anticoagulant.

Last Review Date

03/06/2024