ABSTRACT
Objective:
To evaluate the diagnostic value of the
von Willebrand factor (vWF) GPIb activity to
antigen ratio for
thrombotic thrombocytopenic purpura (TTP) at acute phase.
Methods:
A cohort of 93
patients with suspected TTP and admited to our hospitalfrom January 2018 to December 2019 were prospectively enrolled, we analyzed the levels of vWF GPIb activity and vWF
antigen at acute phase, the
diagnosis of acquired TTP was defined as ADAMTS13 activity<10%.The PLASMIC score and final
diagnosis of included
patients were recorded.
Results:
Twenty-twopatients were diagnosed as TTP, the median (interquartile range) of ADAMTS13 activity were 1.0% (0-7.4%), other
diagnoses included
hemolytic uremic syndrome (HUS, n=8), severe
infection ( n=21),
malignancy( n=3),
connective tissue disease( n=8), et al. The vWF GPIb activity, vWF
antigen, and ratio of vWF GPIb activity to
antigen were all significantly lower in
patients with TTP than in those without ( P<0.05). The ratio of vWF GPIb activity to vWF
antigen <0.75 could yield a sensitivityof 81.8% and a
specificity of 95.2% respectively for TTP. In
patients with PLASMIC score≥6, 88.9%
patients with the ratio of vWF GPIb activity to vWF
antigen <0.75 were confirmed as TTP, and 15.4%
patients with the ratio≥0.75 were confirmed as TTP.
Conclusions:
The ratio of vWF GPIb activity to vWF
antigen based on automaticassays might be useful for
differential diagnosis and stratification of TTP at acute phase, especially when the ADAMTS13 assay is not available in
time.