Acl top 750 las coagulation analyzer

FVIII:C was tested through OSA (ACL TOP 750 LAS Coagulation Analyzer, Werfen) by using 2 different aPTT-based OSA: (1) aPTT-based commercial reagents with colloidal silica (Synthasil, Werfen-IL); (2) ellagic acid, Synthafax (Werfen-IL); The factor VIII OSA relies upon measuring the degree of correction of the aPTT when spiked test plasma is added to FVIII Deficient Plasma. To quantify the FVIII:C level, the clotting time obtained is compared to a standard curve on logarithmic/linear scale graph.

Blood samples for point-of-care INR testing (CoaguChek XS) were obtained from a finger stick puncture in accordance with the CoaguChek XS (Roche Diagnostics) manufacturer’s guidelines during a scheduled outpatient clinic visit at the Department of Rheumatology and Clinical Immunology at the UMC Utrecht, the Netherlands. Each blood sample was analyzed with the CoaguChek XS device immediately after the finger stick. Within 1 hour after the finger stick puncture, phlebotomy was performed to draw citrate blood samples (3.2% sodium citrate blood collection tubes, Vacuette, Greiner Bio-One) for determining the INR in the ISO 15189-accredited Central Diagnostic Laboratory of the UMC Utrecht. Plasma was obtained by centrifugation at 3000×g for 5 minutes. The INR was measured on an ACL top 750 LAS coagulation analyzer (Werfen) with a PT based on Owren’s method with rabbit brain–derived thromboplastin (Technoclot PT Owren, Technoclone) and a PT based on the Quick method with a reagent containing recombinant human tissue factor (RecombiPlasTin 2G, Werfen). The local International Sensitivity Index (ISI) was established with certified plasmas (AK verification kit, Technoclone). The INR assay participates in robust internal and external quality assessment schemes, and local performance characteristics were within the predefined limits stated by the manufacturers.