False-positive detection of IgM anti-severe acute respiratory syndrome coronavirus 2 antibodies in patients with rheumatoid arthritis: Possible effects of IgM or IgG rheumatoid factors on immunochromatographic assay results
Bibliographic record
Abstract
Objectives: The severe acute respiratory syndrome coronavirus 2 causes coronavirus disease 2019. A serological test is conducted to determine prior infection by severe acute respiratory syndrome coronavirus 2. We investigated whether the results of anti-severe acute respiratory syndrome coronavirus 2 antibody tests are modified in patients with rheumatoid arthritis. Methods: Patients in Japan with rheumatoid arthritis were recruited at Sagamihara Hospital from July 2014 to October 2015 ( n = 38; 2014 cohort) and at Tokyo Hospital from June to October 2020 ( n = 93; 2020 cohort). Anti-severe acute respiratory syndrome coronavirus 2 antibodies were measured by electrochemiluminescence immunoassay or immunochromatographic assay. Results: Anti-severe acute respiratory syndrome coronavirus 2 antibodies were not detected in any of the samples from rheumatoid arthritis patients tested by electrochemiluminescence immunoassay. Anti-severe acute respiratory syndrome coronavirus 2 antibodies were detected by immunochromatographic assay in the 3 (7.9%) serum samples in the 2014 cohort and 15 (16.1%) serum samples in the 2020 cohort. The IgM rheumatoid factor levels were increased in rheumatoid arthritis patients with IgM anti-severe acute respiratory syndrome coronavirus 2 antibodies detected by immunochromatographic assay (mean ± standard deviation (IU/ml), 1223.0 ± 1308.7 versus 503.6 ± 1947.2; P = 0.0101). The levels of IgG rheumatoid factor were also upregulated in rheumatoid arthritis patients with IgM anti-severe acute respiratory syndrome coronavirus 2 antibodies detected by immunochromatographic assay (4.0 ± 0.7 versus 2.4 ± 0.9; P = 0.0013). Conclusion: The results of IgM anti-severe acute respiratory syndrome coronavirus 2 antibody testing by immunochromatographic assay are modified by IgM or IgG rheumatoid factors in rheumatoid arthritis patients.
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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 | 0.005 | 0.017 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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".