Assist in distinguishing between inherited and acquired forms of thrombotic thrombocytopenic purpura (TTP). Recommended initial test for the identification of autoantibodies to ADAMTS13, since the ADAMS13 inhibitor test is more specific for acquired TTP than the ADAMTS13 antibody test. If suspicion for TTP remains after a negative result, ADAMTS13 Antibody (3000182) is recommended.
Quantitative Enzyme-Linked Immunosorbent Assay
Light Blue (Sodium Citrate). Refer to Specimen Handling at aruplab.com for hemostasis/thrombosis specimen handling guidelines.
Transfer 1 mL platelet-poor plasma to an ARUP Standard Transport Tube. (Min: 1 mL)
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Serum or EDTA plasma. Clotted or hemolyzed specimens.
Ambient: 2 hours; Refrigerated: Unacceptable; Frozen: 2 weeks (No freeze/thaw cycles.)
0.4 BU (Bethesda Units) or less
The majority of cases of idiopathic thrombotic thrombocytopenic purpura (TTP) are caused by ADAMTS13 autoantibodies. Autoantibodies that neutralize ADAMTS13 function are found in approximately two-thirds of idiopathic cases and can be identified and titered by the ADAMTS13 inhibitor test. Non-neutralizing autoantibodies that result in increased ADAMTS13 clearance, but do not inhibit function, are found in approximately one-third of idiopathic TTP cases. Non-neutralizing antibodies are not detected in the inhibitor test but can be detected by ELISA (ADAMTS13 antibody test). ADAMTS13 autoantibodies are not present in congenital TTP (Upshaw-Schulman syndrome). Correlation with clinical information, ADAMTS13 activity, and other relevant laboratory testing is suggested.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
- von Willebrand Factor Cleaving Protease Inhibitor