Back to hamad.qa
عربي
Staff login
​
​Lab Guide
A B C D E F
G H I J K L
M N O P Q R
S T U V W X
Y Z #

Test ID: ADAMTS13 Activity
ADAMTS13 Activity Assay
Useful For

Aiding in the diagnosis of congenital or acquired (immune) thrombotic thrombocytopenic purpura (TTP).
Method name and description

ADAMTS13 Activity is measured in citrated plasma using a commercially available automated chemiluminescent immunoassay.
Reporting name

ADAMTS13 Activity
Clinical information

TTP is a rare, life-threatening thrombotic microangiopathy characterized by thrombocytopenia and microangiopathic hemolysis, often with neurological and renal involvement.
It is usually acquired due to IgG-mediated inhibition of ADAMTS13, leading to accumulation of large VWF multimers and platelet aggregation.
Urgent plasma exchange should be initiated based on clinical suspicion, without waiting for laboratory confirmation. Severe ADAMTS13 deficiency (<10%) strongly supports the diagnosis.

For suspected TTP, collect the ADAMTS13 sample before plasma exchange or plasma infusion whenever possible, as treatment may alter ADAMTS13 activity results.

In case of low levels of ADAMTS-13 (i.e. ≤30%), the analysis can be complimented with ADAMTS13-Inhibitior testing through the Referral Laboratory (https://www.hamad.qa/EN/LabGuide/Pages/General-Laboratory-Test-Information.aspx).
Aliases

ADAMTS-13

von Willebrand factor–cleaving protease

VWF-cleaving protease
Specimen type / Specimen volume / Specimen container
  • Specimen type: Whole blood in Sodium citrate anticoagulant
  • Volume: Fill the 3 mL sodium citrate tube to the fill line (approximately 2.7 mL blood) to ensure the correct 9:1 blood-to-citrate ratio required for accurate testing.
  • Collection tube: Light blue–top (citrate)
Collection instructions / Special Precautions / Timing of collection

Collect blood by venipuncture as per organization guidelines.
Storage and transport instructions
  • Ensure whole blood reaches the laboratory within 2 hours of collection, maintained at room temperature (15–25 °C).
  • Samples received from other HMC and non-HMC facilities where transportation of whole blood sample to AAH within 2 hours is not feasible, must be processed to prepare Platelet-Poor Plasma (PPP) as follows:
    • Centrifuge the citrated whole blood at 1500 × g for 10 minutes at room temperature.
    • After centrifugation, ensure there is a clear separation of plasma from the cellular components.
    • Carefully transfer the upper plasma layer into a clean plastic tube.
    • Avoid touching or disturbing the buffy coat or red blood cell layer.
    • Re-centrifuge the separated plasma at 1500 × g for 10 minutes.
    • Following the second centrifugation, carefully remove only the upper plasma layer.
    • Leave approximately 250 µL of plasma above the cellular layer and discard the remaining bottom portion to avoid platelet contamination.
    • Aliquot the double-centrifuged plasma into appropriately labeled plastic tubes.
    • Freeze the PPP at −20°C or below immediately after preparation.
    • Do not remix the plasma after centrifugation.
    • Transport the frozen PPP to AAH under frozen conditions to ensure that the specimen remains frozen upon arrival.
    • Frozen PPP is stable for up to 2 years for ADAMTS-13 activity.

Note: The original (mother) citrate tube must always be sent together with the PPP aliquot
Specimen Rejection Criteria
  • Clotted samples.
  • Underfilled or overfilled sample tubes
  • Wrong sample container received.
  • Improper specimen transport temperature (Whole blood sample at 15 – 25°C and Platelet poor plasma must be frozen)
  • Whole Blood exceeding 2 hrs. of collection
  • Grossly hemolyzed sample.
Biological reference intervals and clinical decision values
  • Normal range: 60.6 – 130.6%

This makes autoimmune TTP less likely; therefore, ADAMTS13 inhibitor titer was not performed. A normal ADAMTS13 Activity level does not completely exclude a clinical diagnosis of thrombotic thrombocytopenic purpura (TTP). Note: recent plasma infusion or plasma exchange may raise ADAMTS13 levels above the patient's baseline. Clinical correlation is recommended.

  • Severe deficiency: <10% ADAMTS13 Activity

Severely reduced ADAMTS13 Activity can be observed in congenital/hereditary or acquired thrombotic thrombocytopenic purpura (TTP), or occasionally in other conditions such as hemolytic uremic syndrome (HUS), hematopoietic stem cell and solid organ transplantation, liver disease, sepsis, disseminated intravascular coagulation (DIC), pregnancy, or effects of certain medications (e.g., ticlopidine, clopidogrel, cyclosporine, mitomycin C, quinine, etc.). Clinical correlation is recommended.

  • Partial deficiency: 10.0– 60.6% ADAMTS13 Activity

May be due to other diseases (sepsis, DIC, liver disease). Clinical correlation is recommended.

 

The following interpretive comment is added to each report:

ADAMTS13 Activity is intended to aid in the diagnosis and monitoring of TTP for adult patients only. TTP diagnosis is not solely based on ADAMTS13 Activity results. ADAMTS13 Activity results should be used in conjunction with other clinical and laboratory findings.

Non-specific substrate proteolysis by other plasma proteases or recent plasma transfusion or plasma exchange may falsely raise ADAMTS13 Activity. Markedly elevated endogenous von Willebrand factor (VWF) may falsely lower ADAMTS13 Activity.
Factors affecting test performance and result interpretation
  • ADAMTS13 Activity results are not affected by hemoglobin up to 0.5 g/dL, bilirubin up to 307.8 µmol/L, triglycerides up to 14.13 mmol/L, human anti-mouse antibody (HAMA) up to 1 mg/L, VWF up to 2.0 IU/mL, LMWH and UFH up to 2.0 IU/mL.
  • The presence of rheumatoid factor may cause an underestimation of ADAMTS13 Activity test results. Additional testing may be required.
  • ADAMTS13 is an in vitro commercially available assay that aids in the diagnosis and monitoring of TTP in adult patients. Internal testing has not been performed to establish performance claims in the following settings:
    • Pediatric population (<18 years of age). Current performance claims were established with adult samples.
    • To guide patient management plans. Once diagnosed, TTP patient management and therapy strategies should be based on current guidelines and recommendations.
    • Predicting TTP relapses and recurrence.
Turnaround time / Days and times test performed / Specimen retention time
  • Turnaround time: 24 hours from sample receipt in Aisha Bint Hamad Al-Attiyah Hospital laboratory.
  • Days and Times Test Performed: 24/7
  • Performing Location: Aisha Bint Hamad Al-Attiyah Hospital Laboratory.

 

(For any inquiries related to samples, reports, or specimen transport logistics, or test ordering please contact the Hotline at 4024 8104).

Hamad Medical Corporation

HMC is the principal public healthcare provider in the State of Qatar, delivering the safest, most effective and most compassionate care to each and every one of our patients.

Latest Facebook Posts

Latest Twitter Posts

Privacy Notice. © Copyright - Hamad Medical Corporation by Corporate Communications Dept.
Top