EXPERIENCE WITH USING RAPID MOLECULAR TESTING IN DIAGNOSING PULMONARY AND EXTRA-PULMONARY PEDIATRIC TUBERCULOSIS IN A NON-ENDEMIC SETTING - A RETROSPECTIVE CASE SERIES
Bibliographic record
Abstract
Abstract BACKGROUND Tuberculosis (TB) is a rare but potentially devastating infection among Canadian children. Accurate diagnosis and initiation of treatment are limited in part by the fact that it takes 2–6 weeks for culture results to be confirmed. Xpert MTB/RIF (Xpert) is a rapid, automated molecular assay that has been validated for diagnosing pulmonary but not extra-pulmonary TB in children. OBJECTIVES This was a retrospective study of children investigated for active TB at our facility in order to: 1.Outline demographic characteristics and describe clinical presentations of children diagnosed with active TB. 2.Compare performance of molecular testing (Xpert) to stain and Mycobacterium tuberculosis culture on pulmonary and extra-pulmonary specimens. DESIGN/METHODS We conducted a retrospective chart review of all paediatric patients investigated for active TB at our facility with stain, culture and molecular (Xpert) testing between January 2015 and August 2017. Due to a small number of patients, our data analysis was limited to narrative summary and descriptive statistics. RESULTS A total of 10 children were diagnosed with active TB, including 3 cases of pulmonary, 4 extra-pulmonary and 3 disseminated disease. Age range at diagnosis was 2 months to 16 years, with 3 children younger than 1 year. Most children contracted TB while travelling to and/or being exposed to an index case from endemic areas, including East Asia/Western Pacific (5), South Asia (2) and Africa (1). All children were HIV negative. Time from symptom onset to TB diagnosis and treatment ranged from approximately 4 days to 5 months. Multi-drug resistant TB was confirmed in 1 child. Sadly, 1 child passed away from TB related complications. AFB stain was positive on at least one specimen in 4/10 cases, cultures were positive in 8/10 and molecular testing (Xpert) in 7/10 cases. Time to positive cultures ranged from 10 to 35 days, with an average of 19 days. All cases positive on Xpert were also culture positive. Xpert test diagnosed TB in 5/6 of extra-pulmonary specimens submitted, including pericardial fluid, lymph node tissues and cerebrospinal fluid. CONCLUSION Many paediatric TB patients at our facility are children who have traveled to/have contacts from TB endemic regions, emphasizing the need for obtaining thorough exposure and travel history. Culture and molecular testing demonstrated similar TB detection rates, albeit based on a small patient population. While cultures remain the most reliable diagnostic method, molecular testing may facilitate rapid diagnosis and treatment of pulmonary and extra-pulmonary paediatric TB in a non-endemic setting.
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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 | 0.003 | 0.016 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".