Assays of ADAMTS-13 activity

Area of Science:

• Biochemistry
• Hematology
• Diagnostic Assays

Background:

• Assays for ADAMTS-13 activity are essential for diagnosing thrombotic thrombocytopenic purpura (TTP).
• Existing methods involve substrate proteolysis followed by product quantification.
• These assays utilize various substrates like von Willebrand factor (VWF) and unfolding agents such as urea or guanidine.

Purpose of the Study:

• To review and analyze existing assays for determining ADAMTS-13 activity.
• To highlight the methodologies employed in these assays, including substrate preparation and detection methods.
• To discuss the limitations of current assays in the context of rapid laboratory diagnosis of TTP.

Main Methods:

• Proteolysis of VWF substrates (exogenous or endogenous) by ADAMTS-13.
• Substrate unfolding using urea or guanidine.
• Quantification of cleavage products or residual VWF via electrophoresis, functional assays, or immunoassays (ELISA, IRMA).

Main Results:

• Various methods exist for measuring ADAMTS-13 activity, all involving proteolysis and quantification steps.
• Assays have successfully linked deficient ADAMTS-13 activity to TTP since 1998.
• Current assays are cumbersome, time-consuming, and not yet ideal for rapid diagnosis.

Conclusions:

• Despite their utility in establishing the link between ADAMTS-13 and TTP, current assays require significant improvement.
• The complexity and time-intensive nature of these assays limit their routine use for rapid laboratory diagnosis.
• Further development is needed to create more efficient and physiologically relevant assays for ADAMTS-13 activity.