ADAMTS 13 Antibody

Also Known as (Alias) ATS-13 Antibody
Indications TTP
Method ELISA
Test Information If ADAMTS 13 activity is less than 30%, then reflex testing for an inhibitor and antibody will be performed.  The ADAMTS 13 antibody test uses microtiter wells coated with a recombinant ADAMTS 13 protease.  After incubation with the patient’s plasma, a conjugated anti-human IgG is applied and the test is completed with the change of color as an indication of an antibody.  Test results of 12 – 15 units/mL is borderline positive for an antibody. Results of greater than 15 units/mL is positive.
Additional Test Information Strong antibody-mediated inhibition of ADAMTS13 activity (>90%) is seen in approximately half of the patients with acquired TTP. The presence of this level of inhibition strengthens the case for a diagnosis of TTP. The significance of milder ADAMTS13 inhibition is unclear, particularly when the overall ADAMTS13 level is not severely depressed. The assay used does not distinguish between antibody-mediated and non-specific ADAMTS13 inhibition.

Caution should be exercised in the interpretation of any assay for ADAMTS13; the results should only be considered in the conjunction with the patient’s clinical condition. Previous transfusion, plasma infusion, plasma exchange, or free hemoglobin in the plasma (>2g/L) may affect the level of ADAMTS13 as well as any inhibitors that are present.

Sample Requirements Citrate (blue top)
Requested Volume 5cc Citrate (blue top)
Shipping Information Ship to Bloodworks immediately after draw to ensure the laboratory receives specimen within 4 hours of draw time.  If this is not possible, spin within 4 hours and freeze plasma at -20C,  then ship frozen specimen on dry ice

NOTE: If the sample is received as whole blood after 4 hours of draw time, the sample will need to be redrawn.

Send samples to:
Bloodworks Northwest
Attn:  Platelet Immunology Lab, Rm 619
921 Terry Avenue
Seattle, WA 98104

For additional information, please see Ordering Information

Requisition Form RFT- Platelet Immunology Laboratory
RFT- Hemostasis Reference Laboratory
Transaction Code 3260-03
CPT Codes 83520
Test Schedule Reflexive
Turn around Time (analytic time) 2-3 business days
Report/Results Fax number required to receive report

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