ADAMTS13 Activity with Reflex to Inhibitor

Test Code
ADAMTS13 (14532)

Quest Code

Alias/See Also
Von Willebrand Cleaving Protease

CPT Codes

If ADAMTS13 Activity is ≤30, ADAMTS13 Inhibitor will be performed at an additional charge (CPT code(s): 85335).

Preferred Specimen
1 mL frozen plasma collected in a 3.2% sodium citrate (light blue-top) tube

Minimum Volume

0.5 mL

Platelet-poor plasma: Centrifuge light blue-top tube 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.

Transport Temperature

Specimen Stability
Frozen -20° C: 21 days
Frozen -70° C: 6 months

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
EDTA plasma

Immunoassay (IA)

Setup Schedule
Set up: Sun-Thurs; Report available: 2-4 days

Reference Range
ADAMTS13 Activity 68-163 % Activity
ADAMTS13 Inhibitor <0.4 BEU

For more information on this test, go to:

Clinical Significance
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.

Performing Laboratory
Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92675

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.