Performance evaluation of Revohem^™ FVIII chromogenic and Revohem^™ FIX chromogenic in the CS‐5100 autoanalyser

Abstract

Introduction Chromogenic substrate assay (CSA) reagents Revohem™ FVIII and Revohem™ FIX are now available as in vitro diagnostic reagents for autoanalysers in Japan. In this study, we evaluated the performance of these reagents in the CS‐5100 automated coagulation analyser. Methods We assessed within‐run and between‐day imprecision, on‐board stability and frozen‐storage stability of Revohem FVIII and FIX. Sensitivity to lupus anticoagulant (LA) was examined using LA‐positive patient plasma. Correlations were analysed using plasma samples from normal individuals and patients with haemophilia A (HA) or B (HB) or von Willebrand disease (VWD). Results Imprecision was <2% for Revohem FVIII and <6.5% for Revohem FIX. On‐board storage of Revohem FVIII resulted in a <10% decrease in FVIII levels from baseline at 24 hours, whereas Revohem FIX showed a >10% decrease at 8 hours. Revohem FVIII showed good stability while frozen for 22 days. Although Revohem FIX showed degradation due to freeze‐thawing, a new calibration improved stability up to 22 days. Interference from LA was not observed with Revohem FVIII or FIX. The FVIII CSA‐CSA correlation was excellent in normal (r = 0.9924), HA (r = 0.9945) and VWD (r = 0.9914). The FVIII CSA‐OSA correlation was good in normal (r = 0.8468) and excellent in HA (r = 0.975) and VWD (r = 0.9936). The FIX CSA‐OSA correlation was fair in normal (r = 0.4791) and excellent in HB (r = 0.9501). Conclusion Revohem FVIII and FIX both showed excellent performance in the CS‐5100 analyser. These reagents could be useful in routine laboratory testing for diagnosing and treating haemophilia.

Impact of variation in reagent combinations for one‐stage clotting assay on assay discrepancy in nonsevere haemophilia A

“…Additionally, we could not investigate variations in CSA reagents. Our previous study showed no significant differences between Revohem FVIII chromogenic and Siemens FVIII chromogenic kits, 20 supporting another previous study showing no consistent differences between the three most commonly used kits 27 . On the other hand, another study confirmed the presence of significant differences in FVIII:C Chr results between CSAs 28,29 .…”

“…One‐stage clotting assay for FVIII was carried out on a CS‐5100 analyser (Sysmex) according to the method described in a previous study, 20 with the following modifications. Fifteen microlitres of the plasma sample was diluted with 135 µL of Owren's veronal buffer (OVB; Sysmex).…”

“…A total of 11 reagent combinations, excluding PSL/F8DP‐3 due to unacceptable results in terms of quality control, were used for OSA. FVIII chromogenic substrate assay was carried out using the Revohem FVIII Chromogenic Kit (Sysmex) on an CS‐5100 analyser, as described previously 20 . The incubation time for factor Xa generation is 300 seconds.…”

External quality assessment for one‐stage and chromogenic factor IX assays in samples containing Alprolix (rFIXFc) or Idelvion (rIX‐FP) and evidence that UK National External Quality Assessment Scheme for blood coagulation samples are commutable with patient samples

“…Determination of FIX activity is useful to ensure efficacy of treatment in several settings 1 and is commonly done by one‐stage or chromogenic FIX activity assay 2,3 . There are many different versions of one‐stage assay and at least 3 chromogenic assay kits 4‐7 . There may be clinically relevant differences between results of different FIX assays in FIX concentrates 8 and in haemophilia B patients before 9,10 and after infusion of concentrates 6 .…”

“…2,3 There are many different versions of one-stage assay and at least 3 chromogenic assay kits. [4][5][6][7] There may be clinically relevant differences between results of different FIX assays in FIX concentrates 8 and in haemophilia B patients before 9,10 and after infusion of concentrates. 6 There are particularly marked differences between results with different methods in the presence of extended half life concentrates.…”