Reconsidering Absolute Diagnostic Thresholds in Intrahepatic Cholestasis of Pregnancy [A159]
Bibliographic record
Abstract
INTRODUCTION: Practice guidelines utilize absolute bile acid levels to diagnose intrahepatic cholestasis of pregnancy (ICP) or to determine its severity, but the normal reference range varies by laboratory. We sought to evaluate variation in total bile acid assays by laboratory, testing method, and fasting state. METHODS: Using a search engine, we compiled a list of laboratories located within North America, the United Kingdom, and Australia. We obtained laboratory-specific information on bile acid assays, including testing method, reference range, and fasting requirements. Reference ranges were evaluated in relation to ICP severity thresholds (40 or 100 micromoles/L). RESULTS: We identified seven laboratories with total bile acid assays: four in the U.S., one in Canada, one in the U.K., and one in Australia. Three labs also offered a fractionated assay (ARUP, Lab Corp, Quest). Depending on the test employed, the upper limit of normal for total bile acids ranged from 6.8 to 19.0 micromoles/L. Assay methods included chromatography/mass spectrometry, quantitative enzymatic, and spectrophotometry. Fasting was preferred or required in 10 of 11 assays—either overnight, 8 hours, 12–14 hours, or duration unspecified. Utilizing ICP severity thresholds, a total bile acid level greater than 40 micromoles/L or 100 micromoles/L was 2–6 times or 5–15 times the upper limit of normal, respectively, depending on the assay used. CONCLUSION: Multiple bile acid assays are available, but the normal reference range varies due to assay methodology and fasting recommendations. Thus, caution is warranted if a definitive bile acid is utilized to define disease severity or perinatal risk.
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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 | 0.021 | 0.066 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.004 | 0.005 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".