The effect of ABO blood group on the diagnosis of von Willebrand disease.

In order to firmly establish a normal range for von Willebrand factor antigen (vWF:Ag), we determined plasma vWF:Ag concentrations in 1,117 volunteer blood donors by quantitative immunoelectrophoresis. The presence of the ABO blood group has a significant influence on vWF:Ag values; individuals with blood group O had the lowest mean vWF:Ag level (74.8 U/dL), followed by group A (105.

Loss of the largest von Willebrand factor multimers from the plasma of patients with congenital cardiac defects.

We identified a consecutive series of 12 children with noncyanotic congenital cardiac lesions with loss of the largest plasma von Willebrand factor (vWF) multimers determined by SDS-agarose electrophoresis. Seven had previous histories of mucocutaneous hemorrhage; ten had a prolonged bleeding time. Analysis of the factor VIII molecular complex revealed that six patients had reduced vWF measured both immunologically (vW:Ag) and by ristocetin cofactor assay (vW:rist).

Serial studies of protein C and its plasma inhibitor in patients with disseminated intravascular coagulation.

This study was undertaken to determine the levels of protein C antigen and activity and protein C inhibitor in sequential plasma samples of disseminated intravascular coagulation (DIC) patients. Our normal range for both protein C antigen and activity is 70 to 130 U/dL, and protein C inhibitor is 65 to 135 U/dL. A decreased level of protein C activity was found in 96% of the plasma samples from individuals with DIC; the protein C antigen was decreased in 73%.

Comparison of the sensitivity of commercial APTT reagents in the detection of mild coagulopathies.

This study was undertaken to evaluate the precision and sensitivity of three different commercial APTT reagents containing the activators kaolin, micronized silica, or ellagic acid. These reagents varied greatly in their ability to detect mild coagulopathies. The ellagic acid reagent was able to detect the mildest deficiencies for the most common coagulopathies.