Clinics and Departments

Laboratory Services

Lab Dept:

Coagulation

Test Name:

ANTITHROMBIN III, CHROMOGENIC

General Information

Lab Order Codes:

ATIII

Synonyms:

ATIII; AT3; ATIII, functional; Anti - Thrombin III

CPT Codes:

85300 – Clotting inhibitors or anticoagulants; antithrombin III activity

Test Includes:

Chromogenic Activity reported as a %.

Logistics

Test Indications:

Antithrombin inactivates thrombin and other serine proteases (activated Factors 12, 11, 10 and 9). In the absence of heparin, this process is relatively slow. In the presence of heparin, antithrombin almost instantaneously inactivates thrombin. Heterozygous deficiencies are associated with a thrombotic tendency. Homozygous state is probably not compatible with life. This activity test will detect abnormalities of both decreased levels of normal molecule and/or normal amounts of an abnormal molecule. Therefore, this activity (chromogenic) test is preferred.

Lab Testing Section:

Coagulation

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

4 hours

Special Instructions:

Deliver immediately to the laboratory.

Specimen

Specimen Type:

Whole blood

Container:

Light Blue top (Buffered Na Citrate 3.2%) tube

Draw Volume:

1.8 mL blood (in 2 mL tube) or 2.7 mL blood (in a 3 mL tube).

This test may be combined with other coagulation testing.

Collection:

A clean venipuncture is essential. Mix thoroughly by gentle inversion.

Patient’s with a hematocrit level >55% must have a special tube made to adjust for the hematocrit; contact laboratory for special tube.

Special Processing:

N/A

Patient Preparation:

None

Sample Rejection:

Improper tube; clotted sample; underfilled tubes; mislabeled or unlabeled specimens

Interpretive

Reference Range:

Age:

Range (%):

0 – 5 days:

51 – 75%

5 days – 1 month:

54 – 80%

1 – 3 months:

63 – 93%

3 – 6 months:

85 – 109%

>6 months:

92 – 118%

Critical Values:

N/A

Limitations:

If specimen contains heparin (drawn after heparin flush or after receiving heparin), results may be erroneous.

Methodology:

Chromogenic Activity Assay

References:

Harmening DH (1997) Clinical Hematology and Fundamentals of Hemostasis

Updates:

3/26/2008: Removed statement, do not tube through pneumatic tube system.



  Lab Test Directory
    Chemistry
    Coagulation
    Flow/Immunology
    Hematology
    Microbiology/ Virology
    Other Fluids
    Pathology
    Serology
    Transfusion Services
    Urine/Stool

  Search Lab Test Directory
    List All Documents

  Lab Staff

  E-mail Lab Services