The Nijmegen ultra-sensitive Bethesda Assay detects very low-titer factor VIII inhibitors in patients with congenital and acquired hemophilia A.

Background: An inhibitor can develop in congenital hemophilia A (HA) patients against exogenous infused factor (F)VIII, whereas in acquired HA (AHA) inhibitors initially develop against endogenous FVIII. Inhibitors can be detected with the Nijmegen Bethesda Assay (NBA), which has an international cut-off level of 0.60 Nijmegen Bethesda Units/mL (NBU/mL).

The factor VIII inhibitor assays can be standardized: results of a workshop.

Background: The Bethesda and the Nijmegen assays are commonly used for the measurement of inhibitor levels in hemophilia A patients. Despite test innovations, the between-laboratory coefficient of variation (CVb) of factor VIII inhibitor test data in external quality surveys remains very high (40-60%) with a high degree of false-negative and false-positive results resulting in undesired effects on treatment.

Objectives: Organization of a workshop in order to address the causes of this phenomenon and to suggest ways to improve the assays.

Use of the platelet function analyzer to minimize bleeding complications after renal biopsy.

Background: The bleeding time is frequently used to screen primary haemostasis before surgical procedures, although it poorly predicts the risk of hemorrhage. The platelet function analyzer (PFA), which is also used to screen primary haemostasis, has a higher sensitivity and other advantages, like patient friendliness, higher degree of objectivity and analytical reliability, but needs more extensive clinical validation.

Methods: We compared the predictive values of the PFA-CTs (closure times) and bleeding time for bleeding events after renal biopsy.