Performance evaluation of the new Roche Lupus Screen and Lupus Confirm Russell’s viper venom reagents on the cobas t 711 analyzer for lupus anticoagulant detection

Current guidelines recommend using at least two different assays for lupus anticoagulant (LA) detection. One such assay is the dilute Russell's viper venom time (dRVVT). This study aimed to evaluate the analytical performance of the Lupus Screen and Lupus Confirm dRVVT reagents (Roche Diagnostics) on the cobas t 711 analyzer and to compare their diagnostic performance against an established reagent pair (LA1/LA2, Siemens) using the Sysmex CN-6000 analyzer (Sysmex Corporation) for LA detection. Repeatability was assessed by testing lyophilized quality control plasmas 20 times in a single run. Reproducibility was evaluated over at least five days with duplicate testing. A total of 101 anonymized patient samples were analyzed with both Roche and Siemens reagents on their respective platforms. Statistical analysis was performed using GraphPad Prism software version 9.5.0 (GraphPad Software, San Diego, CA, USA). Diagnostic performance was assessed via positive percentage agreement (PPA), negative percentage agreement (NPA), and overall rate of agreement (ORA). The within-run and between-run CVs were < 2%. Results obtained with the Roche and Siemens reagents were strongly correlated (r = 0.950, 0.923, and 0.877 for screen, confirm, and normalized screen/confirm ratios, respectively; all p < 0.001) and bias were acceptable. Assuming Siemens reagents as reference, PPA, NPA, and ORA were 92.42%, 100%, and 95.05%, respectively. The Lupus Screen and Lupus Confirm reagents demonstrated excellent analytical and diagnostic performance and are well-suited for LA detection in non-anticoagulated patient samples.