VWF Protease Activity w/Reflex

Test Code

VWFRF

Alias/See Also

ADAMTS13 Activity with Reflex to Inhibitor
VWF Cleaving Protease (vWF-CP)
von Willebrand Factor Protease Activity

Quest Code
145328

CPT Codes
85397

Includes

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

Preferred Specimen

1 mL platelet-poor plasma from a 3.2% sodium citrate (light blue-top) tube, transferred to a plastic screw-cap vial

Minimum Volume

0.5 mL

Instructions

Please submit a separate, frozen vial for each special coagulation assay ordered.

Centrifuge light blue-top tube 15 minutes at approx. 1500 x 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 aliquoted tube containing plasma for and additional 15 minutes. Transfer platelet-poor plasma into a new plastic vial and freeze within 60 minutes of collection. Plasma must be free of platelets (< 10,000/mcL).

Transport Temperature

Frozen

Specimen Stability

Room temperature: unacceptable
Refrigerated: unacceptable
Frozen (-20^oC): 21 days

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

EDTA plasma

Methodology
Immunoassay (IA)

This test was performed using a kit that has not been cleared or approved by the FDA. The analytical performance characteristics of this test have been determined by Quest Diagnostics. This test should not be used for diagnosis without confirmation by other medically established means.

Setup Schedule

Sun, Tues-Fri a.m.

Report Available

2-4 days

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
Chantilly, VA

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.