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Test Code ADAMS ADAMTS13 Activity Assay, Plasma


Ordering Guidance


Consider ordering in patients with known diagnosis of congenital, immune, or acquired thrombotic thrombocytopenic purpura.



Specimen Required


Patient Preparation: Fasting preferred

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

Submission Container/Tube: Plastic vials

Specimen Volume: 2 mL in 2 plastic vials each containing 1 mL

Collection Instructions:

1. Specimen must be collected prior to replacement therapy.

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

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

4. Aliquot plasma (1 mL per aliquot) into 2 separate plastic vials, leaving 0.25 mL in the bottom of centrifuged vial.

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

Specimen Stability Information: Frozen 2 years

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.


Secondary ID

620816

Useful For

Assisting with the diagnosis and monitoring of congenital, immune, or acquired thrombotic thrombocytopenic purpura

Method Name

Fluorescence Resonance Energy Transfer (FRET)

Reporting Name

ADAMTS13 Activity Assay, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Thrombotic thrombocytopenic purpura (TTP), a rare (estimated incidence of 3.7 cases per million) and potentially fatal thrombotic microangiopathy syndrome, is characterized by a pentad of symptoms: thrombocytopenia, microangiopathic hemolytic anemia (intravascular hemolysis and presence of peripheral blood schistocytes), neurological symptoms, fever, and kidney dysfunction. A large majority of patients initially present with thrombocytopenia and peripheral blood evidence of microangiopathy and, in the absence of any other potential explanation for such findings, satisfy criteria for early initiation of plasma exchange, which is critical for patient survival. TTP may rarely be congenital (Upshaw-Shulman syndrome) but, far more commonly, is acquired. Acquired TTP may be considered primary or idiopathic (the most frequent type) or associated with distinctive clinical conditions (secondary TTP) such as medications, hematopoietic stem cell or solid organ transplantation, sepsis, and malignancy.

 

The isolation and characterization of an IgG autoantibody frequently found in patients with idiopathic TTP clarified the basis of this entity and led to the isolation and characterization of a metalloprotease called ADAMTS-13 (a disintegrin and metalloprotease with thrombospondin type 1 motif 13 repeats), which is the target for the IgG autoantibody, leading to a functional deficiency of ADAMTS-13. ADAMTS-13 cleaves the ultra-high-molecular-weight multimers of von Willebrand factor (VWF) at the peptide bond Tyr1605-Met1606 to disrupt VWF-induced platelet aggregation. The IgG antibody prevents this cleavage and leads to TTP. Although the diagnosis of TTP may be confirmed with ADAMTS-13 activity and inhibition studies, the decision to initiate plasma exchange should not be delayed pending results of this assay.

 

ADAMTS13 activity results can have an impact on overall survival, ultimate clinical outcome, responsiveness to plasma exchange, and relapse are still controversial in recent literature. Therefore, clinical correlation is essential.

Reference Values

≥70%

Although not verified, the pediatric (<1 years old) reference range could be similar to or lower than that of adults.

Interpretation

Less than 10% ADAMTS-13 activity is highly indicative of thrombotic thrombocytopenic purpura (TTP) in an appropriate clinical setting.

Day(s) Performed

Monday through Friday, Sunday

Report Available

1 to 3 days

Specimen Retention Time

7 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

85397

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ADAMS ADAMTS13 Activity Assay, P 53622-7

 

Result ID Test Result Name Result LOINC Value
620816 ADAMTS13 Activity 53622-7
620819 Interpretation 69049-5

Forms

If not ordering electronically, complete, print, and send one of the following with the specimen:

-Renal Diagnostics Test Request (T830)

-Coagulation Test Request (T753)