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ADAMTS13 Activity and Inhibitor (Southeast Michigan Only)

VWF Cleaving Protease Activity, Protease Activity Inhibitor for TTP

Test Codes

EPIC: LAB1231487, Beaker: XADMA, Mayo: ADM13

Department

Send Outs

Specimen Collection Criteria

Collect: Two Light Blue-top Sodium Citrate tubes

Physician Office/Draw Specimen Preparation

For optimal results, maintain whole blood sodium citrate specimens at room temperature (20-26°C or 68-78.8°F) prior to transport. Transport whole blood to the Laboratory within 4 hours of collection. If transport within 4 hours is not possible, the following procedure must be followed for accurate results:

1. Centrifuge the capped tube at 1500 x g for 15 minutes.
2. Transfer plasma with a plastic pipette into a plastic polypropylene centrifuge tube, cap and centrifuge an additional 15 minutes at 1500 x g to obtain platelet poor plasma (PPP) which has a platelet count less than 10 bil/L. Plasma with a platelet count of less than 10 bil/L is critical for accurate results.
3. Immediately remove only the top two-thirds of the PPP and transfer it into five plastic tubes.
4. Freeze (-20°C/-4°F or below) the PPP specimens immediately.
5. Transport frozen on DRY ICE. Specimen must remain frozen during transport.

Preparation for Courier Transport

Transport: 4.0 mL plasma, frozen (-20°C/-4°F or below). (Minimum: 2.0 mL)

Rejection Criteria

• Specimens collected in EDTA.
• Specimens not collected and processed as indicated.

In-Lab Processing

Specimens must be processed immediately upon receipt in the Laboratory:

1. Centrifuge the capped tube at 1500 x g for 15 minutes.
2. Transfer plasma with a plastic pipette into a plastic polypropylene centrifuge tube, cap and centrifuge an additional 15 minutes at 1500 x g to obtain platelet poor plasma (PPP) which has a platelet count less than 10 bil/L. Plasma with a platelet count of less than 10 bil/L is critical for accurate results.
3. Immediately remove only the top two-thirds of the PPP and transfer it into five plastic tubes.
4. Freeze (-20°C/-4°F or below) the PPP specimens immediately.

Transport: 4.0 mL plasma, frozen (-20°C/-4°F or below). (Minimum: 2.0 mL) 

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): unacceptable
Refrigerated (2-8°C or 36-46°F): unacceptable
Frozen (-20°C/-4°F or below): 14 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Monday – Friday.
Results available in 1-3 days.

Reference Range

By report.

Test Methodology

Fluorescence Resonance Energy Transfer Assay (FRET).

Clinical Utility

ADAMTS13 is a regulator of the interaction of platelets with von Willebrand factor. Absent or low ADAMTS13 activity appears to allow formation of platelet microthrombi, which in turn obstruct arterioles and capillaries. Low levels of ADAMTS13 are associated with a clinical diagnosis of Thrombotic thrombocytopenic purpura (TTP). Severe deficiency of less than 5% appears to be a relatively specific finding in thrombotic microangiopathy patients with a clinical diagnosis of TTP or Upshaw-Schulman Syndrome. Patients with low levels of activity and the presence of an inhibitor increase specificity for a diagnosis of idiopathic TTP.

CPT Codes

85397, 85335 (if appropriate), 85335 (if appropriate).

Contacts

Last Updated

10/25/2024