Comparison of Endoscopy-Based and Serum-Based Methods for the Diagnosis of<i>Helicobacter pylori</i>
Bibliographic record
Abstract
UNLABELLED: Available commercial tests for the diagnosis of Helicobacter pylori infection are based on different types of antigen preparations and hence the diagnostic utility differs substantially. OBJECTIVE: To assess the diagnostic value of the determination of Immunoglobulin (Ig) A and IgG antibodies to H pylori whole cell (WC) and IgG antibodies to cytotoxin associated gene A (CagA) using an in-house ELISA in relation to the results obtained with different invasive methods. METHODS: The study population consisted of 251 Mexican adults, mean age 53 years, age range 15 to 92 years and female to male ratio of 1.5. Peptic ulcer disease was present in 10.8% of these patients, 5.2% had gastric cancer, 11.2% had esophagitis and 72.9% had nonulcer dyspepsia. Biopsy specimens from the body and the antrum of the stomach were obtained for culture, histology and rapid urease test. ELISAs to detect IgA and IgG WC and CagA antibodies were performed using serum. RESULTS: H pylori status was established by the results of the invasive tests. Eighty (31.9%) patients positive to the three tests and 38 (15.1%) negative to all the tests were identified. Based on this result, the sensitivity and specificity of the serology assays were 97.5% and 78.9% for the IgG WC and 70% and 73.7% for the IgA WC, respectively. However, if H pylori status was defined by the positive result of at least one or two invasive diagnostic tests, the sensitivity for the IgG WC decreased to 87.3% and 66.7% respectively, but the specificity was essentially the same. Similar results were obtained for the sensitivity and specificity of IgA using the same criteria. A low CagA prevalence was observed (39%). CONCLUSIONS: Testing for serological IgG antibodies to H pylori WC was the best to assess whether infection by H pylori was present. Neither the IgA WC nor the IgG CagA ELISAs add significant value in the diagnosis of H pylori.
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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 | 0.004 | 0.013 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".