Testing the APTTO clot-waveform tool to identify causes of prolonged APTT
Multicenter External Validation of the APTTO Predictive Model Based on Clot Waveform Analysis for the Assessment of Prolonged Activated Partial Thromboplastin Time
This project will test whether the APTTO model, using clot waveform data from routine APTT tests, can tell which patients with prolonged APTT (and normal PT) have a pathological cause and can distinguish lupus anticoagulant from factor deficiencies.
Quick facts
| Study type | Observational |
|---|---|
| Enrollment | 1500 (estimated) |
| Sex | All |
| Sponsor | Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz Academic / other |
| Locations | 16 sites (Leganés, Madrid and 15 other locations) |
| Trial ID | NCT07418099 on ClinicalTrials.gov |
What this trial studies
This multicenter observational cohort uses routine laboratory data from several Spanish hospitals to externally validate the APTTO predictive model in patients with prolonged APTT and normal PT. All data, including clot waveform analysis parameters generated on ACL TOP analyzers with SynthASil reagent, are collected as part of standard care without extra blood draws or changes to clinical management. The original APTTO coefficients and predefined cut-offs will be applied without recalibration to measure discrimination, calibration, and decision-analytic performance, and secondary subgroup and sensitivity analyses will examine robustness. The study follows TRIPOD guidance for prediction-model validation.
Who should consider this trial
Good fit: Patients of any age with an APTT ratio ≥ 1.25 and a normal PT whose APTT was run on an ACL TOP analyzer using the SynthASil reagent and have clot waveform analysis data available are ideal candidates.
Not a fit: Patients with prolonged PT or combined PT/APTT prolongation, those whose samples were not processed on ACL TOP with SynthASil, or samples that fail the study's preanalytical standards are unlikely to benefit from the APTTO model.
Why it matters
Potential benefit: If successful, this model could help clinicians and laboratories identify patients with clinically relevant causes of prolonged APTT more quickly and reduce unnecessary additional testing.
How similar studies have performed: Internal validation of the APTTO model demonstrated good discrimination and calibration, but external validation in independent cohorts has not yet been completed.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: 1. Patients of any age (pediatric and adult populations) undergoing coagulation testing with: \- Prolonged activated partial thromboplastin time (APTT), defined as an APTT ratio ≥ 1.25. \- Normal prothrombin time (PT), according to local laboratory reference ranges. 2. Availability of clot waveform analysis (CWA) data obtained during routine APTT testing using: * Optical coagulation analyzers (ACL TOP platform). * Silica-based APTT reagent (SynthASil®). 3. Completion of the standard laboratory evaluation for prolonged APTT as part of routine clinical care, when clinically indicated. 4. Samples collected and processed in accordance with the standardized preanalytical protocol defined in the study SOP. 5. Patients evaluated in either: * Preoperative assessment, or * Routine clinical practice (non-preoperative setting). Exclusion Criteria: 1. Prolonged prothrombin time (PT) or combined prolongation of PT and APTT. 2- Inadequate preanalytical conditions, defined as non-compliance with the study SOP, including but not limited to: * Incorrect blood-to-anticoagulant ratio. * Delayed plasma processing beyond protocol-defined time limits. * Inadequate centrifugation or plasma quality. 3\. Absence of required CWA data or unavailable clot waveform images. 4\. Samples in which APTT values are outside the measurable range of the analyzer, preventing extraction of CWA-derived parameters. 5- Patients with missing essential clinical or laboratory data required for application of the APTTO models.
Where this trial is running
Leganés, Madrid and 15 other locations
- Hospital Universitario Severo Ochoa — Leganés, Madrid, Spain (Recruiting)
- Hospital de la Santa Creu i Sant Pau — Barcelona, Spain (Recruiting)
- Hospital Universitario Arnau De Vilanova — Lleida, Spain (Recruiting)
- Hospital Universitario 12 de Octubre — Madrid, Spain (Recruiting)
- Hospital Universitario Clínico San Carlos — Madrid, Spain (Not_yet_recruiting)
- Hospital Universitario Fundación Jiménez Díaz — Madrid, Spain (Recruiting)
- Hospital Universitario Gregorio Marañón — Madrid, Spain (Not_yet_recruiting)
- Hospital Universitario Puerta de Hierro — Madrid, Spain (Not_yet_recruiting)
- Hospital Universitario Ramón y Cajal — Madrid, Spain (Recruiting)
- Hospital Clínico Universitario Virgen de la Arrixaca — Murcia, Spain (Not_yet_recruiting)
- Clínica Universidad de Navarra — Pamplona, Spain (Not_yet_recruiting)
- Hospital Clínico Universitario de Salamanca — Salamanca, Spain (Not_yet_recruiting)
- Complexo Hospitalario Universitario de Santiago — Santiago de Compostela, Spain (Not_yet_recruiting)
- Hospital Clínico Universitario de Valladolid — Valladolid, Spain (Recruiting)
- Complexo Hospitalario Universitario De Vigo — Vigo, Spain (Not_yet_recruiting)
- Hospital Clínico Universitario Lozano Blesa — Zaragoza, Spain (Not_yet_recruiting)
Study contacts
- Principal investigator: Diego Velasco Rodríguez, MD, PhD — Hospital Universitario Fundación Jiménez Díaz / IIS-FJD
- Study coordinator: Diego Velasco Rodríguez, MD, PhD
- Email: diego.velascor@quironsalud.es
- Phone: +34 669 98 04 32
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.