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Alias Names: von Willebrand Cleaving Protease
Methodology: FRET-Based Kinetic Assay
Edit Date: 1/1/2009
Performed: Monday-Friday
Released: 4-6 days after setup at PeaceHealth Laboratories’ reference lab.
CPT Code: 85397-90
Specimen Collection Details
Collection: One 4.5 mL light blue top tube (sodium citrate).
Handling: Centrifuge to produce platelet poor plasma, at least 1500 G for 15 minutes. transfer to a plastic vial. Freeze within 4 hours of collection. NOTE: Provide history for all hemostasis work-ups and list any prescription or non-prescription medication taken in past 10 days.
Stability: 2 months frozen. Unstable ambient or refrigerated.
Standard Volume: 1 mL plasma.
Minimum Volume: 0.5 mL plasma.
Transport: Frozen on dry ice.
Comments: Inhibitors will no longer be performed on specimens with ADAMTS13 activity greater than 30. ADAMTS13 (also known as VWF cleaving protease) is a metalloprotease that cleaves VWF. ADAMTS13 activity is deficient in plasma of TTP patients. Thrombatic thrombocytopenic purpura (TTP) is a life-threatening, rare condition characterized by formation of microvascular thrombi, a low platelet count, hemolysis with red cell fragmentation, and CNS and renal dysfunction. Diagnosis of TTP is made clinically, and its diagnosis and differentiation from other thrombotic microangiopathies is often difficult. Recent findings suggest that absent or low levels of ADAMTS13 activity may allow the accumulation of ultra-large multimers of von Willebrand factor (ULVWF) in plasma. (1,2) It is hypothesized that these ULVWF cause the intravascular platelet aggregation characteristic of TTP.
Rejection Criteria: EDTA specimen.

PeaceHealth Laboratories