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Test Code LAB8818 Antithrombin Antigen, Plasma

Additional Codes

ATTI

Useful For

Assessing abnormal results of the antithrombin activity assay (ATTF / Antithrombin Activity, Plasma), the recommended primary (screening) antithrombin assay

 

Diagnosing antithrombin deficiency, acquired or congenital, in conjunction with measurement of antithrombin activity

 

An adjunct in the diagnosis and management of carbohydrate-deficient glycoprotein syndromes

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Plasma Na Cit


Ordering Guidance


For monitoring treatment of antithrombin deficiency disorders, including infusion of antithrombin therapeutic concentrate, order ATTF / Antithrombin Activity, Plasma.



Necessary Information


If patient is being treated with heparin, this should be noted as heparin treatment may lower plasma antithrombin.



Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation: Fasting preferred

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Polypropylene vial

Specimen Volume: 1 mL

Collection Instructions:

1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.

2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

3. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.

4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, at-40° C or below.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reference Values

Adults: 80-120%

Normal, full-term newborn infants may have decreased levels (≥35-40%) that reach adult levels by 180 days postnatal.*

Healthy, premature infants (30-36 weeks gestation) may have decreased levels that reach adult levels by 180 days postnatal.*

*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing.

Day(s) Performed

Monday through Friday

CPT Code Information

85301

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ATTI Antithrombin Antigen, P 27812-7

 

Result ID Test Result Name Result LOINC Value
ATTI Antithrombin Antigen, P 27812-7

Interpretation

Hereditary antithrombin deficiency is much less common than acquired deficiency. Diagnosis of hereditary deficiency requires clinical correlation, testing of both antithrombin activity and antithrombin antigen, and may be aided by repeated testing and by family studies. DNA-based diagnostic testing may be helpful but is generally not readily available.

 

Acquired antithrombin deficiency may occur in association with a number of conditions (see Clinical Information). The clinical significance (thrombotic risk) of acquired antithrombin deficiency is not well established, but accumulating information suggests possible benefit of antithrombin replacement therapy in carefully selected situations.(4)

 

Increased antithrombin activity has no definite clinical significance.

Method Description

This assay is performed on the Instrumentation Laboratory ACL TOP using the Diagnostica Stago LIATEST AT III kit. Antithrombin antigen is determined using automated latex immunoassay (LIA) methodology. Patient plasma, containing antithrombin antigen, is combined with a latex reagent containing rabbit antihuman antibodies. An antigen-antibody reaction takes place, causing the latex particles to agglutinate and form aggregates. The aggregates form diameters greater than the wavelength of the light (405 nm) passing through causing absorption of the light. This change in absorption is measured over time and reported as delta optical density. The increase in absorption is proportional to the concentration of antithrombin antigen present in the sample.(Package insert: LIATEST AT III. Diagnostica Stago S.A.S.; Rev. 02/2015)

Report Available

Same day/1 to 4 days

Specimen Retention Time

7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Method Name

Latex Immunoassay (LIA)