Evaluation of factor VIII deficient plasmas

Standardized plasma substrates are commonly used in coagulation assays to ensure consistency across laboratories. Prior research has shown that locally collected hemophilic plasma can serve as a reference material for factor VIII assays. However, variability in commercial substrates remains a concern. This gap motivated a comparative study to assess the suitability of various immunodepleted plasmas. No prior work had resolved whether all commercial substrates perform equally in assays with high-purity concentrates. Existing methods rely on hemophilic plasma as a gold standard. The study aimed to clarify whether commercially available substrates could reliably replace locally collected samples. Differences in assay drift and slope consistency were previously unexamined in this context. This research addresses a critical need in diagnostic standardization.

The aim of this study was to evaluate the suitability of commercially available immunodepleted plasmas as alternatives to locally collected hemophilic plasma in one-stage factor VIII assays. Researchers sought to determine if these substrates produce comparable results across clinical samples and concentrates. The motivation arose from the need for standardized reference materials in coagulation testing. Variability in commercial substrates could affect diagnostic accuracy. The study focused on comparing five commercial plasmas with local hemophilic plasma. It also examined how these substrates perform with monoclonal and recombinant concentrates. The goal was to identify which substrates maintain assay consistency. This work addresses diagnostic reliability in hemophilia testing.

The study compared immunodepleted plasmas from Organon Teknika, Dade, Stago, Diagen, and SNBTS with local hemophilic plasma. Five clinical plasma samples and four concentrates were tested against British Standard plasma and an International Standard concentrate. Multiple laboratories performed one-stage factor VIII assays using these substrates. Potency values were calculated and compared across all samples. Buffer blank times and standard line slopes were analyzed for consistency. Drift in assay results was monitored at the start and end of each test. The study included intermediate purity, conventional high purity, monoclonal, and recombinant concentrates. Results were statistically evaluated for significant differences from hemophilic plasma.

Potency values for most commercial plasmas were not significantly different from local hemophilic plasma in clinical samples. Dade and Diagen showed minor deviations on specific samples. Buffer blank times and standard line slopes were consistent across all substrates. A positive drift was observed with the Immuno substrate, while Organon Teknika showed a negative drift. Intermediate and conventional high purity concentrates yielded consistent results with all substrates. Monoclonal and recombinant concentrates showed lower potencies with immunodepleted plasmas. Dade and Stago substrates gave significantly lower results for monoclonal concentrates. Diagen, Dade, and Stago showed significant differences for recombinant concentrates.

Most commercial immunodepleted plasmas are suitable replacements for local hemophilic plasma in one-stage assays of clinical samples. They perform comparably with intermediate and conventional high purity concentrates. However, some substrates produce lower results with monoclonal and recombinant concentrates. Hemophilic plasma remains preferable for very high purity products. The study confirms that commercial substrates maintain assay consistency in most cases. Drift patterns and slope consistency support their general reliability. Dade and Stago substrates showed significant deviations in high purity assays. These findings align with the authors' claim that commercial plasmas are suitable in most contexts.