Epic Code LAB3440 ADAMTS13 Activity

Important Note

ADAMTS13 Evaluation is ordered for performance of ADAMTS13 Activity.

ADAMTS13 Evaluation is a reflexive testing algorithm for evaluation of TTP. Activity is always performed. If result is <= 30%, the inhibitor assay (1297) is performed. If inhibitor result is <= 0.7 Inhibitor Units, the antibody assay (1299) is performed.

Test Name Alias

Metalloproteinase | AdamTS13 | VWF Cleaving Protease Activity | 7007 | 1230100295

Interface Order Alias

11724

Ordering Instructions

Patient should be off warfarin (Coumadin) for at least 2 weeks.

Specimen Requirements

Specimen Type: Platelet Poor Plasma
Container/Tube: Blue top (3.2% Sodium Citrate)
Volume to draw: 2.7 mL Whole Blood (Tube must be full) or 1.8 mL Whole Blood (Tube must be full)
Requested Volume: 3 0.5mL aliquots of plasma

Minimum volume: 2 0.4 mL aliquots of plasma

Collection Instructions:

Centrifuge and remove plasma within 1 hour of collection.
Freeze aliquot in plastic transport tubes immediately
To obtain a coagulation plasma sample, centrifuge the capped specimen tube at a speed and time required to consistently produce platelet-poor plasma (platelet count < 10,000/uL). The centrifugal speed and duration to accomplish this must be established in the individual laboratory. Our laboratories use centrifuges at 3,000 to 4,000 rpm for ten minutes or higher speed and shorter duration centrifuges.
When removing plasma to send for coagulation testing, it is important NOT to go all the way down to the cells. Leave a minimum 1/4 inch of plasma sitting on cells. This layer contains the platelets which were separated from the plasma during spinning. The platelets interfere with coagulation testing so we leave this layer undisturbed.

Specimen Transport Temperature

Frozen

Test Frequency

Test performed Monday - Friday. Turn-around time 3 - 5 days.

Reference Range

ADAMTS13 Activity ≥ 67%

Performing Department

Send Outs

Performing Department Laboratory Location

Send Out to Versiti Wisconsin

Methodology

ADAMTS13 activity is measured by Fluorescence Resonance Energy Transfer (FRET) with a synthetic substrate.7 ADAMTS13 inhibitor is determined using mixing studies; one inhibitor unit is defined as the concentration of inhibitor able to reduce the ADAMTS13 activity of an equal volume of normal pooled plasma by half.8 The ADAMTS13 antibody assay detects IgG antibody serologically by ELISA.

CPT

85397

85335-Factor inhibitor test (if appropriate)

83520-Antibody (if appropriate)

Epic Test ID

1230100295

Reviewed Date

03/6/2024

Orderable Regions