Fecal Calprotectin: A Comparison of Two Commercial Enzymoimmunoassays and Study of Fecal Extract Stability at Room Temperature
Bibliographic record
Abstract
BACKGROUND: The aims of the study were: 1) to compare the fecal calprotectin (fCal) assay results with Calprolab™ ELISA (HRP) (Calpro AS) versus our routine method, Elia™ fluoroenzymoimmunoassay (Thermo Fisher), and 2) to determine whether the fCal assay results do not vary following storage of the extract at room temperature for 4 days with the Calpro AS buffer, this being the estimated shipment time from the home of the patient, and an aspect little studied to date. METHODS: The fCal was determined in 198 patients divided into three groups: inflammatory bowel disease (IBD), organic intestinal disease, and functional intestinal disorders. Fecal extraction was carried out using the Roche Diagnostics kit with the corresponding specific buffers. RESULTS: The fCal assay with the Thermo Fisher method was found to be more sensitive but less specific than with the Calpro AS technique. The positive predictive value was low (just over 50%), though the negative predictive value was high (over 90%) with both methods. The likelihood ratios revealed small but occasionally important pre- versus post-test differences. When we compared the two methods, the Spearman correlation coefficient (ρ) was 0.819 (95% CI: 0.768 - 0.860) (P < 0.0001), reflecting a positive correlation. Similarly, when stratifying the fCal results into < 50 µg/g, 50 - 100 µg/g and > 100 µg/g, the resulting Cohen's kappa coefficient was 0.7766 (95% CI: 0.7025 - 0.8507), reflecting a substantial agreement between both methods. The stability of fCal was high in fecal extracts with the Calpro AS extraction buffer at room temperature for 4 days, which yielded a Spearman correlation coefficient of 0.951 (95% CI: 0.933 - 0.965), when the results were compared to those of the recent extracts (P < 0.0001). CONCLUSIONS: A positive correlation was observed between the two methods. In view of the high negative predictive value obtained with fCal, the presence of organic disease is highly unlikely in the presence of a normal concentration of this marker. We also confirmed the excellent stability of fCal in fecal extracts with the Calpro AS extraction buffer stored at room temperature. Thus, and for the sake of convenience and hygiene, it would be ideal for the patient to perform the extraction at home.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.012 | 0.009 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".