Scientific basis

References and model limits

The lab uses two complementary maps: the classic cascade to organize PT/aPTT and the cell-based model to explain in-vivo hemostasis. Simulations are conceptual and have not been validated as a diagnostic device.

Source
Hoffman M, Monroe DM. A cell-based model of hemostasis (2001)
Foundation for initiation, amplification, and propagation on tissue-factor-bearing cells and activated platelets.
Adcock DM et al. Activated partial thromboplastin time and prothrombin time mixing studies (2023)
Explains how mixing studies help distinguish factor deficiency from an inhibitor after an unexpected prolonged screening test.
Bachler M et al. Influence of factor XII deficiency on aPTT (2019)
Supports the key distinction between a prolonged aPTT and actual bleeding risk in factor XII deficiency.
Dorgalaleh A et al. Laboratory diagnosis of factor XIII deficiency (2016)
Supports targeted investigation of factor XIII when routine PT and aPTT do not explain a bleeding phenotype.
James PD et al. ASH/ISTH/NHF/WFH guidelines on VWD diagnosis (2021)
Supports integrating bleeding history with specific VWF antigen, activity, and factor VIII testing rather than excluding VWD with routine screening alone.
Devreese KMJ et al. ISTH guidance for lupus anticoagulant detection (2020)
Supports the screen–mix–confirm framework and careful interpretation of phospholipid-dependent assays and anticoagulant interference.
Levi M et al. Guidelines for diagnosis and management of DIC (2009)
Supports combining clinical context, serial laboratory testing, and a validated scoring approach rather than relying on one isolated marker.

How to interpret the app

  • PT and aPTT reference intervals vary with reagent, instrument, population, and laboratory.
  • The simulator predicts qualitative patterns; it does not calculate real seconds, INR, bleeding risk, or therapeutic dosing.
  • Factor XII deficiency can markedly prolong aPTT without the bleeding phenotype typical of factor VIII, IX, or XI deficiency.
  • Factor XIII deficiency can cause bleeding while PT and aPTT remain normal.