External Multicenter Validation of the APTTO Model for Prolonged APTT Using Clot Waveform Analysis

Condition(s) studied

Investigational drug(s) / intervention(s)

Clot waveform analysis-based risk stratification (APTTO models): Application of the APTTO predictive models (APTTO1 and APTTO2) to clot waveform analysis parameters generated during routine activated partial thromboplastin time testing, for research purposes only. The model output does not influence clinical management or surgical decision-making during the study.

Study summary

Prolonged activated partial thromboplastin time (APTT) is a frequent laboratory finding that may reflect a broad spectrum of underlying conditions, ranging from benign laboratory abnormalities to clinically relevant hemostatic disorders. Clot waveform analysis (CWA), automatically generated during routine APTT testing by optical coagulation analyzers, provides additional quantitative and qualitative information on clot formation dynamics.

The APTTO model is a previously developed two-step predictive algorithm based on CWA features designed to estimate the probability of a pathological cause of prolonged APTT and to differentiate lupus anticoagulant from intrinsic pathway factor deficiency or von Willebrand disease. Internal validation has demonstrated good discrimination and calibration.

This multicenter observational study aims to perform an external validation of the APTTO model in independent patient cohorts, assessing its discrimination, calibration, and decision-analytic performance without model updating.

Eligibility

Primary outcome measure(s)

• Discriminatory performance of the APTTO model — Baseline (at the time of prolonged APTT laboratory assessment)
  Discrimination of the APTTO1 and APTTO2 models for identifying the cause of prolonged activated partial thromboplastin time (APTT), assessed by the area under the receiver operating characteristic curve (AUC) in an independent multicenter cohort.

Trial sites (16)

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