What does ADAMTS13 do?
The ADAMTS13 enzyme cuts von Willebrand factor into smaller pieces to regulate its interaction with platelets. By processing von Willebrand factor in this way, the enzyme prevents it from triggering the formation of blood clots in normal circulation.
What is a normal ADAMTS13 level?
Normal plasma ADAMTS13 antigen levels span a concentration of 740-1420 ng/ml (median 1080 ng/ml) resulting in an ADAMTS13 activity to antigen ratio of 0.48 to 1.68 U/mug.
How long does an ADAMTS13 test take?
Tests
| Test Name | STAT Turnaround Time | Sample Requirement |
|---|---|---|
| ADAMTS13 Gene Sequencing | 48 hours (M-F, two consecutive business days required) | EDTA whole blood |
| ADAMTS13 Inhibitor | < 24 hours (7 days a week) | citrated plasma |
| Alpha-2 Antiplasmin Activity | < 1 week | citrated plasma |
| Anti-CFH Antibody | 48 hours | serum |
What protein is cleaved by ADAMTS13?
von Willebrand factor-
ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13)—also known as von Willebrand factor-cleaving protease (VWFCP)—is a zinc-containing metalloprotease enzyme that cleaves von Willebrand factor (vWf), a large protein involved in blood clotting.
What causes low ADAMTS13?
Decreased ADAMTS13 activity (equal to or less than 68%) can be observed in idiopathic (autoimmune-related) TTP, TMA syndrome, congenital ADAMTS13 deficiency (Upshaw- Schulman syndrome) and secondary to other clinical conditions such as HUS, ITP, solid organ or bone marrow transplantation, sepsis, DIC, HIV infection.
How does ADAMTS13 cause TTP?
The deficiency of ADAMTS13 leaves unchecked the hyperadhesive vWF unfolded under high shear stress in the microvessels, resulting in the formation of platelet thrombi, which in turn causes TTP.
How is ADAMTS13 deficiency treated?
Plasma exchange is the mainstay of therapy Congenital TTP requires plasma infusion or exchange depending on the patient’s severity of ADAMTS13 deficiency.