PB0552 - Performance evaluation of the ACTICHROME Heparin Anti-Xa™ assay for the quantitative determination of unfractionated heparin and low-molecular-weight heparin plasma concentrations.

Background: The ACTICHROME Heparin Anti-Xa™ assay (Horiba Medical) is a newly launched, specific, easy to use and fully automated chromogenic assay for the quantitative determination of plasma concentrations of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH). Data on its analytical performance in routine laboratory practice are scarce.

Aims: To evaluate the analytical performances of the ACTICHROME Heparin Anti-Xa™ assay performed on the Yuzimen G800, including within-run precision, between-run imprecision, sample carryover, and comparability.

Methods: The study was conducted in the core laboratory of a tertiary University Hospital (Pitié-Salpêtière, Paris, France). Within-run (32 replicates) and between-run imprecision (25 runs) were evaluated using 2 levels (high and low) of quality controls. Sample carryover was assessed by testing samples with high and low concentrations of UFH/LMWH. Comparability was assessed with a widely used anti-Xa assay (STA-Liquid Anti-Xa®, Stago, Asnières, France) performed on a STA-R Max analyzer, using residual anonymized samples in accordance with the Clinical Laboratory Standards Institute guidelines. Passing Bablok and Bland Altman analyses were used for the comparison.

Results: Overall, coefficients of variation were < 7.0% for within-run precision and < 10.5% for reproducibility (Table 1). We did not observe any sample carryover. Passing Bablok regression analyses demonstrated excellent correlations between the ACTICHROME Heparin Anti-Xa™ assay and the predicate assay in both samples from patients treated with UFH (n=51; Pearson r=0.921) and those from patients treated with LMWH (n=51; Pearson r=0.987). Bland-Altman analyses revealed high agreement between the ACTICHROME Heparin Anti-Xa™ assay and the predicate assay in both samples from patients treated with UFH (Figure 1A) and those from patients treated with LMWH (Figure 1B).

Conclusion(s): The ACTICHROME Heparin Anti-Xa™ assay demonstrates robust analytical performance for the quantitative determination of plasma concentrations of UFH and LMWH and good agreement with a relevant comparator method, supporting its use in routine laboratory practice.