Unexplained bleeding disorders in the Netherlands

Bleeding Disorder of Unknown Cause In the Netherlands (BDUC-iN Study)

Maastricht University Medical Center · NCT07454161

This project will try to find blood-based and genetic reasons for unexplained bleeding in people referred to hemostasis centers in the Netherlands.

Quick facts

Study typeObservational
Enrollment500 (estimated)
Ages12 Years and up
SexAll
SponsorMaastricht University Medical Center (other)
Locations8 sites (Nijmegen, Gelderland and 7 other locations)
Trial IDNCT07454161 on ClinicalTrials.gov

What this trial studies

Adults and children with an increased bleeding tendency who remain undiagnosed after standard coagulation testing are enrolled at specialized Dutch hemostasis centers. Participants provide blood samples for extended hemostasis testing and genetic analysis and complete validated patient-reported outcome questionnaires about bleeding impact and quality of life. The study also documents how care is currently delivered to these patients to identify gaps and opportunities for better management. Results aim to improve diagnostic accuracy and inform more tailored treatment and care pathways for people with bleeding disorder of unknown cause (BDUC).

Who should consider this trial

Good fit: People referred to a (pediatric) hemostasis specialist with an abnormal ISTH-BAT score or clinical bleeding concern who have normal or non-explanatory standard coagulation test results are ideal candidates.

Not a fit: Patients who already have a clear laboratory diagnosis (for example, von Willebrand disease or a known platelet function disorder) or whose bleeding is explained by non-hemostatic causes are unlikely to gain benefit from this study.

Why it matters

Potential benefit: If successful, the study could lead to clearer diagnoses and more targeted treatment plans that reduce bleeding and improve daily functioning and quality of life.

How similar studies have performed: Previous research has shown that extended hemostasis testing and genetic analyses can identify causes in some previously unexplained cases, but a substantial proportion of BDUC cases remain without a clear etiology.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Referred to a (pediatric) hemostasis specialist for evaluation of bleeding tendency.
* Increased bleeding tendency based on: Abnormal International Society on Thrombosis and Haemostasis Bleeding Assessment Tool (ISTH-BAT) score (≥ 5 in women age 18-30; ≥ 6 in women age 31-51, ≥ 7 in women age 52 or older; ≥4 in men and ≥ 3 in children) OR Clinical gestalt according to the investigating physician
* Absence of diagnostic test results for a bleeding disorder in standard laboratory hemostasis tests:
* Complete blood count: Hemoglobin \> 6.0 mmol/L; thrombocyte count \> 100 x10\^9/L
* Prothrombin (PT) and activated Partial Thromboplastin Time (aPTT): within local reference range, or prolonged without explanatory factor deficiency
* Fibrinogen activity, von Willebrand Factor (VWF) antigen \& activity, Factor VIII, IX, XI and XIII: within local reference range or abnormal but not explaining bleeding phenotype
* Light transmission aggregometry (LTA): Not diagnostic for a platelet function
* Kidney function: eGFR \> 45 ml/min
* Liver function: ALAT, bilirubin \< 3 x upper limit of normal

Exclusion Criteria:

* Use of medication interfering with laboratory hemostasis tests which cannot be stopped before blood withdrawal
* Pregnancy or lactation at moment of inclusion
* Presence of an established bleeding disorder
* Presence of an acquired cause or another explanation for the increased bleeding tendency
* Inability to provide informed consent

Where this trial is running

Nijmegen, Gelderland and 7 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Hemorrhagic Disorders, Bleeding Disorder of Unknown Cause, Bleeding disorder of unknown cause, Hemostasis, Diagnosis, Management, Pathofysiology, Quality of life

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.