Test Directory

• ADAMTS13 Activity

ADAMTS-13 is a zinc metalloprotease that cleaves ultra large vWF multimers. Studies have shown that low levels of ADAMTS-13 activity are associated with thrombotic thrombocytopenic purpura (TTP), a life-threatening hematological condition characterized by a low platelet count, microvascular thrombi, red cell fragmentation, and renal complications. Congenital TTP is a rare inherited disease caused by mutations within the ADAMTS-13 gene, which result in the production of non-functional protein. The acquired form of TTP is an autoimmune-like disorder caused by the development of autoantibodies to ADAMTS-13 that inhibits enzyme activity.

Specimen Type: Citrated Plasma

Collection Container: Light Blue Top (Sodium Citrate) 

Desired Specimen Volume: 1 mL

1. Collect a light blue top (sodium citrate) tube via venipuncture.

1. Separate plasma from cells within one hour of collection.
2. Transfer 1 mL of citrated plasma to a clear aliquot tube (screw cap). Freeze immediately.
3. Please submit a separate, frozen vial for each special coagulation assay ordered.

Transport to the laboratory frozen. 

• Gross hemolysis
• Grossly lipemic
• Grossly icteric

 See patient report.

Results are reported using international units (IU) per mL and not in percent (%), typically described in many studies. To convert to %, multiply IU/mL by 100%. For example, 0.3 IU/mL would be equivalent to 30% (0.3 IU/mL x 100%).

• ADAMTS13 Activity with Reflex to Inhibitor
• VWF Cleaving Protease