Five-year experience in remote diagnosis of von Willebrand disease in Russia

Accurate and timely laboratory diagnosis plays a key role in specifying the causes of hemorrhagic events both in children and adults. However, due to the rarity and diversity of some bleeding disorders, a full spectrum of laboratory testing may not be available in certain regions or hospitals. Taking into account these limitations, a programme of remote diagnosis of von Willebrand disease (VWD) was initiated in 2019. The aim of our study was to assess the results of the programme. In accordance with the study protocol, peripheral blood samples from patients suspected of VWD were collected at local healthcare facilities and, after initial sample preparation, were transferred to the Laboratory of Clinical Hemostasis of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. Ethical approval was not required since the study only involved the use of anonymized and generalized retrospective data obtained during routine clinical practice. Coagulation analysis included tests for von Willebrand factor antigen (vWF:Ag), von Willebrand factor ristocetin cofactor activity (vWF:RCo), and factor VIII (FVIII) clotting activity. From 04 November 2019 to 31 December 2023, we received a total of 512 frozen samples from 375 children aged under 18 years (the mean age was 10 years (1 month – 17 years)) and 139 adult patients (the mean age was 35 (18–72) years) from 21 regions of the Russian Federation. Pre-analytical errors were identified in 42 (8.2%) cases. Decreased vWF activity ( 50%) was found in 125 (26.6%) patients. VWF activity 30% was registered in 52 (11.1%) patients, while vWF:RCo 50% and 30% – in 73 (15.5%) cases. In 68 (54.4%) patients, laboratory findings were consistent with vWD type 1, in 50 (40%) cases testing results were indicative of vWD type 2, and 7 (5.6%) patients had vWD type 3. Thirty (6.4%) patients had decreased FVIII/vWF:Ag ratio. Type 2N VWD was found in one woman with low FVIII activity (the FVIII binding activity of VWF was 2%, normal range: 70–130%). The implementation of this programme has allowed us to specify a diagnosis in 125 patients without their in-person presence and regardless of their place of residence. This expands our possibilities of detecting VWD in patients living in regions with limited diagnostic capacity.