PB1060 - Multicentre Performance Evaluation and Reference Range for the Quantitative Determination of Factor IX Activity on the cobas t 711 Analyser

Tuesday, July 12, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Martin Büchsel, MD

Physician
University Medical Center Freiburg, Faculty of Medicine, University of Freiburg
Freiburg, Baden-Wurttemberg, Germany

Co-Author(s)

JC

Jessica Creaghan

Specialist Biomedical Scientist
Sheffield Haemostasis and Thrombosis Centre
Sheffield, England, United Kingdom
UG

Ulrich Geisen

MD
Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg
Freiburg, Baden-Wurttemberg, Germany
PJ

Petra Jilma

MD
Department of Laboratory Medicine, Medical University of Vienna
Vienna, Wien, Austria
RJ

Robert Jones

Senior Biomedical Scientist/Study Investigator
Sheffield Haemostasis and Thrombosis Centre
Sheffield, England, United Kingdom
Steve Kitchen, PhD

Lead Scientist
Sheffield Haemophilia and Thrombosis Centre
sheffield, England, United Kingdom
GR

Gergely Rozsnyai

Senior Study Manager
Roche Diagnostics International Ltd
Rotkreuz, Zug, Switzerland
PQ

Peter Quehenberger

Professor
Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
Vienna, Wien, Austria

Background: Factor IX (FIX), a vitamin K‐dependent plasma protease, plays an essential role in coagulation. A multicentre evaluation of an activated partial thromboplastin time (aPTT)‑type assay for quantitative determination of FIX activity was performed.

Aims: Evaluate the analytical performance of the one-stage FIX assay on the high-throughput cobas t 711 analyser (Roche Diagnostics International Ltd, Rotkreuz, Switzerland).

Methods: Analytical performance was evaluated at three sites (Freiburg, Sheffield, Vienna; October 2020–February 2021) using anonymised, ethically approved, 3.2% citrated, residual routine plasma samples. Five human plasma pools and two controls were used to determine assay repeatability (one run/site; n=21 replicates/sample), intermediate precision and total reproducibility (five aliquots/sample/day for five days); coefficients of variation (CVs; samples >1.0 IU/dL FIX activity) and standard deviations (SDs; samples ≤1.0 IU/dL FIX activity [repeatability/intermediate precision only]) were calculated. Using three sets of ≥120 samples, method comparison (versus Siemens Coagulation Factor IX Deficient Plasma [with Dade Actin FSL] on Sysmex CS-5100 analyser) and lot-to-lot variability (three reagent lots) were evaluated using Passing-Bablok and Deming regression, respectively; Pearson’s r was calculated. The reference range was determined using three reagent lots (Freiburg only) with fresh plasma samples from 200 healthy individuals aged ≥18 years (not receiving anticoagulants).

Results: Across the three sites, the FIX assay demonstrated repeatability (CV, 1.0–6.3%; SD, 0.0275–0.0303), intermediate precision (CV, 1.7–8.4%; SD, 0.0232–0.191), and total reproducibility (CV, 3.9–20.8%) within the prespecified acceptance criteria. The FIX assay also showed method comparison results (Pearson’s r, 0.993–0.996; Table 1) and lot-to-lot variability (Pearson’s r, 0.997–0.999; Table 2) within the prespecified acceptance criteria. The reference range for FIX activity in healthy adults was 69.6–146 IU/dL.

Conclusion(s): The robust analytical performance of the FIX assay on the cobas t 711 analyser supports routine clinical laboratory practice use.

Study

Funding: Roche Diagnostics International Ltd, Rotkreuz, Switzerland.