INTENDED USE

The IMUBIND® ADAMTS13 ELISA is intended for the measurement of ADAMTS13 protein in human plasma. The assay is limited to ‘For Research Use Only’.

EXPLANATION OF THE TEST

ADAMTS13, also known as von Willebrand Factor (vWF) cleaving protease, is a zinc metalloproteinase that cleaves ultra large vWF multimers (UL-vWF) between Tyr(1605)-Met(1606), located in the A2 region of vWF.1,2 A deficiency of ADAMTS13 activity (<5%) can lead to an accumulation of UL-vWF multimers.3 The UL-vWF multimers bind to receptors on platelets inducing platelet aggregation and formation of intravascular thrombi.

Congenital TTP is a rare inherited disorder resulting from mutations in the ADAMTS13 gene. Genetic alterations have been identified at many sites within the ADAMTS13 gene, which can lead to the production of non-functional ADAMTS13 protein.4,5 The acquired form of TTP is an autoimmune disorder caused by the development of autoantibodies to ADAMTS13 that inhibit its activity or may cause a reduction in antigen levels.6-8

PRINCIPLE OF THE METHOD

Diluted plasma samples are added to microwells coated with a monoclonal antibody that binds to ADAMTS13. During an incubation period, ADAMTS13 in a sample binds to the antibody coated to the wells. Following a washing step, a biotinylated rabbit anti-ADAMTS13 polyclonal antibody is added to the microwells, which binds to ADAMTS13 protein captured on the plate during a short incubation period. A streptavidin-horseradish peroxidase conjugate (SA-HRP) is added to the microwells to complete the formation of the antibody-enzyme detection complex. Following another washing step, the addition of a perborate-3,3’-5,5’-tetramethylbenzidine (TMB) substrate and its subsequent reaction with the HRP present generates a blue colored solution. The reaction is stopped by adding sulfuric acid, which turns the solution color yellow. Measuring the solution absorbance at 450 nm and extrapolating the value with those of a standard curve determines the level of ADAMTS13 in the diluted plasma sample.