Analytical Performance and Quality Indicators of Fully Automated Immunoassays for sFlt-1 and PlGF
Bibliographic record
Abstract
BACKGROUND: The ratio of the antiangiogenic factor, soluble fms-like tyrosine kinase 1 (sFlt-1), to the proangiogenic factor, placental growth factor (PlGF), is associated with increased risk of preeclampsia. Here, we describe an analytical evaluation of the Elecsys sFlt-1 and PlGF assays at the first North American site in which they were clinically implemented. METHODS: The analytical evaluation included short- and long-term imprecision, method comparison, accuracy, linearity, sample stability, limit of quantification verification, and measurement uncertainty. Quality indicators were also evaluated, including turnaround time and repeat test frequency. RESULTS: Short-term (13-day) and long-term (12-month) imprecision for sFlt-1 and PlGF were <4% CV. Method comparison (n = 40) between Roche cobas e602 and e411 exhibited r > 0.99 and bias <10%. sFlt-1/PlGF ratio rule-out cutoffs (≤33 and ≤38) and rule-in cutoffs (>38, >85, and >110) exhibited negative percent agreement and positive percent agreement of 100%, respectively (n = 40). During the first 12 months, 257 orders were placed, repeat test frequency was 17.5%, mean time between repeat orders was 23 days, and 72.0% of results were reported within 2 h from sample receipt when quality control was run continuously. CONCLUSIONS: We describe analytical performance parameters and quality indicators of the Elecsys sFlt-1 and PlGF assays, which was the first North American clinical laboratory site to implement these assays in support of the institution's high-risk obstetrical unit.
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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 | 0.027 | 0.039 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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 | 0.000 |
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".