<sup>13</sup>C Urea Breath Test for <i>Helicobacter pylori</i>: Determination of the Optimal Cut-Off Point in a Canadian Community Population
Bibliographic record
Abstract
AIM: To determine the test characteristics and the optimal cut-off point for the (13)C urea breath test ((13)C UBT) in a Canadian community laboratory setting. METHODS: Of 2232 patients (mean age +/- SD: 51+/-21 years, 56% female) who completed a (13)C UBT, 1209 were tested to evaluate the primary diagnosis of (Helicobacter pylori) infection and 1023 were tested for confirmation of eradication following treatment. Cluster analysis was performed on the (13)C UBT data to determine the optimal cut-off point and the risk of false-positive and false-negative results. Additionally, 176 patients underwent endoscopic biopsy to allow validation of the sensitivity and specificity of the (13)C UBT against histology and microbiology using the calculated cut-off point. RESULTS: The calculated cut-off points were 3.09 delta/1000 for the whole study population (n=2232), 3.09 delta/1000 for the diagnosis group (n=1209) and 2.88 delta/1000 for the post-treatment group (n=1023). When replacing the calculated cut-off points by a practical cut-off point of 3.0 delta/1000, the risk of false-positive and false-negative results was lower than 2.3%. The (13)C UBT showed 100% sensitivity and 98.5% specificity compared with histology and microbiology (n=176) for the diagnosis of active (H pylori) infection. CONCLUSIONS: The (13)C UBT is an accurate, noninvasive test for the diagnosis of (H pylori) infection and for confirmation of cure after eradication therapy. The present study confirms the validity of a cut-off point of 3.0 delta/1000 for the (13)C UBT when used in a large Canadian community population according to a standard protocol.
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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 | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".