New quantitative aPTT waveform analysis and its application in laboratory management of haemophilia A patients

Summary Diagnosis of haemophilia A is usually made by the measurement of factor VIII (FVIII) activity that allows categorization of the disease severity. However, tests that assess global haemostasis may better reflect clinical features and give additional clinically relevant information. The aim of this study was to develop a new quantitative activated partial thromboplastin time (aPTT) waveform analysis and compare it with FVIII activities to find out whether waveform parameters are superior determinants of clinical phenotype. A total of 81 haemophilia A patients divided into two groups (37 severe, 44 non‐severe) were included in the study. The control group comprised 101 healthy male volunteers. Quantitative aPTT waveform analysis was performed with Actin FS on BCS (Siemens Healthcare Diagnostics, Marburg, Germany) using three parameters (DELTA, RATIO‐1, RATIO‐2) obtained from a single aPTT measurement with two evaluation modes. FVIII activities were measured by one‐stage clotting and two‐stage chromogenic assay. Statistically significant difference (P