Estimation of Nuwiq (simoctocog alfa) activity using one-stage and chromogenic assays-Results from an international comparative field study.

Background: Accurate determination of coagulation factor VIII activity (FVIII:C) is essential for effective and safe FVIII replacement therapy.

Fviii: C can be measured by one-stage and chromogenic substrate assays (OSAs and CSAs, respectively); however, there is significant interlaboratory and interassay variability.

Aims: This international comparative field study characterized the behaviour of OSAs and CSAs used in routine laboratory practice to measure the activity of Nuwiq (human-cl rhFVIII, simoctocog alfa), a fourth-generation recombinant human FVIII produced in a human cell line.

Plasma factor XIII level variations during menstrual cycle.

Factor XIII (FXIII) has an important role in the control of bleeding through fibrin cross-linking; however, its effect within the menstrual cycle is not fully understood. The aim of this study was to examine changes in FXIII activity during the normal menstrual cycle and correlate FXIII activity with menstrual blood loss. A total of 32 healthy normal women of reproductive age were recruited.

A common F13A1 intron 1 variant IVS1+12(A) is associated with mild FXIII deficiency in Caucasian population.

Mild factor XIII deficiency is an underdiagnosed coagulation disorder. Considering the large number of coding and non-coding polymorphisms identified in the F13A1 gene, there is a possibility that some of these might result in alterations of plasma FXIII levels and cause mild FXIII deficiency. Recently, a homozygous F13A1 gene intron 1 variant (IVS1+12C>A) was found in a patient with FXIII deficiency.