VWF and systemic lupus erythematosus: For the collection of pseudonymized samples for the measurement of factors II, VII, IX, XI, and XIII, as well as lupus screen/confirm, protein C, and von Willebrand factor (vWF) activity, the study protocol was submitted to the Federal Institute for Drugs and Medical Devices (Germany) and the Berlin State Office for Health and Social Affairs (LAGeSo) in accordance with EU and national law as well as local regulatory requirements before the start of sample collection from donors.