Yale New Haven Hospital

Department of Laboratory Medicine
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ADAMTS13 activity w/reflex to inhibitor

Lab Section: 



Lab Location: 

Main Lab

Test ID: 




Fluorescence Resonance Energy Transfer (FRET)




7 days

Specimen Requirements: 

Collection: 2.7 mL Blood in a Blue Top Tube.
Pediatric volume: 2.7 mL.
Handling: Critical: Collection tube volume must be filled. Sample should be sent at room temperature and be processed within 2 hours, if possible.
Unacceptable conditions: Collection tubes not filled to the blue triangle at the top of the tube. Grossly Hemolyzed Specimens
Stability: After removing plasma: 4 hours refrigerated, 6 months at frozen (-70C)



Reflex Criteria: If the ADAMTS13 Activity is <=30%, the Inhibitor assay will be performed at an additional charge.

Clinical Indications: ADAMTS-13 is the protease responsible for cleaving von Willebrand Factor; deficiency of ADAMTS-13 activity has been demonstrated in the plasma of thrombotic thrombocytopenic purpura (TTP) patients. TTP may rarely be congenital (Upshaw-Shulman syndrome), but far more commonly is acquired. About two-thirds of patients with a clinical diagnosis of inherited (Upshaw-Schulman syndrome) or acquired thrombotic thrombocytopenic purpura (TTP) demonstrate <10% activity. Acquired or idiopathic TTP has been associated with the presence of an inhibitory IgG autoantibody leading to a functional deficiency of ADAMTS13. Mild or moderately decreased levels of ADAMTS-13 activity have also been associated with other disease states and conditions.>

Stat testing will only be performed if cleared by a Laboratory Resident.

Reference Interval: 

ADAMTS-13 Activity: => 67% Activity
ADAMTS-13 Inhibitor: <30% Inhibition

CPT Code(s): 


Last Changed: 

12/19/2016 17:55:15

Last Reviewed: 

8/24/2017 3:03:25 PM