ADAMTS13 activity and inhibitor profile

Alphabetical Test listing

ADAMTS13 activity and inhibitor profile-994

Test name:

Test number:

994

Excellian order number:

LAB994

Abbreviation:

MSO

Alternate names:

Metalloprotease
Protease Activity Inhibitor for TTP
von Willebrand Factor Cleaving Protease
Microangiopathy
Thrombotic Microangiopathy
VWF protease activity and inhibitor

Tests included:

Testing begins with the ADAMTS-13 activity assay to evaluate the percent activity. If the ADAMTS-13 activity is less than 30%, an inhibitor screen will be performed to look for specific ADAMTS-13 inhibition. If specific inhibition is apparent, the titer of the inhibitor will be determined.

Useful for:

Assisting with the diagnosis of congenital or acquired thrombotic thrombocytopenic purpura

Patient preparation information:

Fasting preferred

Specimen must be collected prior to replacement therapy

Specimen type:

Sodium citrate (Na cit) plasma

Collection container:

To obtain adequate sample volume please collect 2 tubes:

Lt blue Sodium citrate (Na Cit) - 2.7mL

Volume:

2 mL plasma in 2 plastic vials each containing 1 mL

Collection instructions:

Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical

Coag – tube fill guidelines

Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times to prevent clotting

Processing instructions:

Centrifuge
Transfer plasma into a plastic vial
Centrifuge a second time
Aliquot plasma (one mL per aliquot) into two seperate screw cap transfer vial/tube (Mayo T914), leaving 0.25 mL in the bottom of the centrifuged vial
Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C or, ideally, below -40 degrees C.

Transport container:

Screw cap transfer vial/tube (Mayo T914)

Transport and stability:

Frozen (strict) - 14 days

Refrigerated - NO

Ambient - NO

Specimen retention time:

7 days

Performing lab:

Mayo Clinic Laboratories (ADM13): R-NX

Days set up:

Mo - Fr, Su

TAT:

3 days

Method:

Fluorescence Resonance Energy Transfer (FRET)

Reference ranges:

ADAMTS13 ACTIVITY ASSAY: > or =70%

ADAMTS13 INHIBITOR SCREEN: Negative

ADAMTS13 BETHESDA TITER: <0.4 BU

Clinical information:

Less than 10% ADAMTS-13 activity is highly indicative of thrombotic thrombocytopenic purpura (TTP) in an appropriate clinical setting. The presence of ADAMTS-13 inhibition (positive inhibitor screen) with a measurable antibody titer is most consistent with an acquired TTP.

CPT codes:

85397
85335 (if appropriate)

Date created:

05/31/2022

Revised date:

02/28/2023

Review date:

02/28/2023