Possibility of potential VWD misdiagnosis or misclassification using LIA technology and due to presence of rheumatoid factor

von Willebrand's disease (VWD) is now recognised to be the most common inhe rited bleeding disorder and is due to defects and/or deficiencies in von Wi llebrand factor (VWF). The latex immune-assay (LIA) procedure has become a popular VWF:Ag detection methodology because of the ability to automate tes ting. In this report, we present findings which urge caution when normal LI A results are obtained co-incident to striking clinical findings strongly s uggestive of VWD, or previous laboratory findings consistent with VWD. As i llustrated by a relevant case study, normal LIA results may lead to an "inc orrect diagnosis" of "not VWD" or to a potential subtype misdiagnosis, shou ld they be accepted without cross-confirmation using alternative VWF method ologies. (C) 2001 Wiley-Liss, Inc.