Comparison of Six Dilute Russell Viper Venom Time Lupus Anticoagulant Screen/Confirm Assay Kits
Bibliographic record
Abstract
BACKGROUND: The normalized dilute Russell viper venom time (DRVVT) ratio provides a robust assay methodology for lupus anticoagulant (LA) detection. OBJECTIVES: We evaluated six normalized DRVVT LA screen and confirm systems for inter-method consistency. Reagents were purchased from Diagnostica Stago, Inc. (Parsippany, NJ); Precision BioLogic Inc. (Halifax, Nova Scotia, Canada); Siemens Healthcare Inc. (Deerfield, IL); TCoag (Parsippany, NJ); Instrumentation Laboratories (Bedford, MA); and Sekisui Diagnostics (Pfungstadt, Germany). METHODS: For all assays, we employed the STA-R Evolution automated coagulometer, adhering to manufacturers' instructions. LA-positive and LA-negative plasma controls were purchased from Diagnostica Stago and pooled normal plasma (PNP) was purchased from Precision BioLogic. We computed the mean of the reference interval (MRI) and action limits for all kits using LA-negative aliquots from locally sourced normal subjects (n = 42). We then assayed locally sourced LA-positive plasmas (n = 43) and using analysis of variance compared uncorrected screen/confirm ratios and screen/confirm ratios that were normalized using MRI and mean PNP results. RESULTS: The grand mean action limit, MRI + 3 SD, derived from the local normal plasmas, was 1.2, confirming the manufacturers' recommended limits; however, limits must be locally computed. The all-sample p value was less than 0.001, indicating heterogeneity among ratios. When Sekisui ratios were excluded, the p value was 0.14, thus indicating that this method introduced the major difference among methods. Mean screen/confirm ratios computed from LA-positive specimens were 1.91 to 2.04 for reagent systems other than Sekisui, which instead yielded a mean ratio of 1.198, indicating that this method was relatively insensitive to LA. A negative bias was recorded by two lots from the Sekisui system for LA-positive specimens. Screen/confirm ratios from combined LA-positive and LA-negative samples generated a combined range of 1.59 to 1.67 for all reagents except Sekisui, which instead yielded 1.09. The within-run percent coefficient of variation (CV%) was less than 5.0% using all samples. Between-run CV% using Diagnostica Stago LA-positive and LA-negative controls was less than 5.5%. CONCLUSIONS: DRVVT screen/confirm ratios discriminate between LA-positive and LA-negative samples and generally provide acceptable reproducibility. Ratio results may vary among reagent-instrument combinations. In this study, normalization added little to the clinical result interpretation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.019 | 0.031 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".