Laboratory Medicine Program

ADAMTS-13 Inhibitor

Clinical Decription:
The ADAMTS 13 protease is responsible for cleaving ultra large vWF multimers. Autoantibodies inhibit this activity and the non-cleaved ULVWF accumulates in plasma. This is believed to be the major cause for thrombotic thrombocytopenic purpura (TTP). The assay allows for the differentiation of congenital (Upshaw-Schulman Syndrome, USS, rarely seen and presenting in childhood) from acquired TTP. Antibodies are not seen in USS, only in acquired TTP. The ADAMTS 13 activity assay results are reviewed with the antibody results to provide the interpretation.

Method: ELISA; Manual

Component Tests Used: ADAMTS-13 Activity, ADAMTS-13 Inhibitor

Reference Ranges Used:
< 12 U/mL Negative | 12 - 15 U/mL Indeterminate | > 15 U/mL Positive

Specimen Type: Citrated plasma
Collected In: 3.2% Sodium Citrate
Volume: 1.0 mL (minimum: 1.0 mL)

Shipping: Send frozen on dry ice.

Special Instructions: The specimen must be double-centrifuged to obtain a platelet-poor plasma specimen (Plt <10x10E9/L): 1. Immediately centrifuge specimen at 1500xG for 10 minutes. 2. Separate the plasma from the platelet/buffy coat and transfer into a clean plastic tube. 3. Centrifuge the separated plasma at 1500xG for 10 minutes. 4. Transfer 1.0 to 2.0 mL of the double-centrifuged plasma into a clean plastic tube, leaving approx. 200 uL for discard. 5. Freeze plasma aliquot immediately for storage. Maintain frozen for shipping and handling.

Testing Schedule(s): Weekly.

Turnaround Time: 7 days

For more information, call 416.340.5227 or 1.866.865.5227