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ADAMTS13 Panel

Justification

This panel will confirm a diagnosis of TTP, differentiate between inherited and acquired forms of TTP, and provide an assessment of antibody level. ADAMTS13 Activity is diagnostic for Thrombotic Thrombocytopenic Purpura (TTP) when ADAMTS13 Activity levels are below 5-10%. Consider other Thrombotic Microangiopathies (TMAs), such as atypical Hemolytic Uremic Syndrome (aHUS), for ADAMTS13 levels above 10%. Early diagnosis and administration of correct treatment is paramount for TTP and aHUS. Testing for the presence of an inhibitor to ADAMTS13 helps differentiate between inherited and acquired Thrombotic Thrombocytopenic Purpura (TTP), while the ADAMTS13 Antibody assay provides a quantitative assessment of anti-ADAMTS13 antibody level. Rarely, cases of acquired TTP may occur due to antibodies that mediate increased clearance of ADAMTS13 but do not inhibit enzyme activity - these antibodies would be detected in the ADAMTS13 Antibody assay but not the ADAMTS13 Inhibitor assay.

Panel Component Tests

ADAMTS13 Activity ADAMTS13 Inhibitor ADAMTS13 Antibody

STAT: < 24 hours (7 days a week)

ELISA

Draw Tube: Blue Top

Sample Type: Citrated Plasma

DRAW KITS AVAILABLE

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED Citrated Plasma 1mL 0.5mL Room Temp.: 7 days
Refrigerated: 7 days
Frozen (-20C): 2 weeks
Frozen (-80C): 6 months
ALTERNATIVE - - - -
REJECTION CRITERIA Thawed in transit if shipped frozen, refrozen, clotted sample
SPECIAL INSTRUCTIONS Mark Saturday delivery on FedEx airbill if shipping on a Friday.

General Information

METHODOLOGY ELISA
STAT TAT < 24 hours (7 days a week)
STAT TAT Performance > 90% of results released in 24 hours 7 days a week
ROUTINE TAT < 24 hours (M-F)
ALTERNATIVE NAMES VWF Cleaving Protease Activity, VWF Cleaving Protease Inhibitor, ADAMTS13 Inhibitor Screen, ADAMTS13 Antibody Titer
DESCRIPTION Chromogenic ELISA for the determination of ADAMTS-13 activity in human plasma. ADAMTS-13 is an enzyme that specifically cleaves unusually large von Willebrand Factor multimers, which induce platelet thrombus formation under high shear stress. If the activity of ADAMTS-13 is lowered for some reason, unusually large VWF multimers may accumulate. Limitations: Samples containing EDTA cannot be used because EDTA is a strong inhibitor of ADAMTS13 function. Hemolysis does not affect assay performance with samples containing up to 200mg/dL of hemoglobin. Lipemia does not affect assay performance with samples containing of up 300 mg/dL of lipids. Icterus does not affect assay performance with samples containing up to 15 mg/dL of bilirubin (both conjugated and unconjugated).
LIMITATIONS -
NORMAL RANGE Normal
ASSOCIATED TESTING ADAMTS13 Gene Sequencing; aHUS Genetic Panel; TMA-Complete Genetic Panel
REFERENCES

1. Moake, MD. Thrombotic microangiopathies. NEJM. 2002;347(8):589-600.
2. Tsai, HM. Autoimmune Thrombotic Microangiopathy: Advances in Pathogenesis, Diagnosis, and Management. Semin Thromb Hemost. 2012;38(05):469-482.
3. Sahud, M, Ero, M, et al. von Willebrand Factor-cleaving protease inhibitor in a patient with human immunodeficiency syndrome-associated thrombotic thrombocytopenic purpura. British Journal of Haematology. 2002;116:909-911.
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED Yes

Test Codes

ORDER CODE -
CPT CODE 85397*2, 85335, 83520
LOINC CODE 53622-7, 34590-0, 40824-5