P773 Increased detection rates of primary syphilis by PCR in a provincial laboratory
Bibliographic record
Abstract
<h3>Background</h3> North America is experiencing an exponential rise in the numbers of infectious syphilis cases. The United States of America had 9.5/100,000 cases in 2017 which is a 10.5% increase from 2016 and a 72.7% increase from 2013. This trend is no different in Canada with Alberta being particularly afflicted as one of the provinces with higher rates. Alberta had a 250% increase in the number of infectious syphilis cases in 2018 compared with 2017 (1380 vs 535) (Figure 1). It is no surprise that the laboratories are experiencing a similar rise in the volume of syphilis tests. Polymerase chain reaction (PCR) for detection of primary syphilis is a relatively new test method in the armamentarium of diagnostic tests for syphilis and is not widely available mainly due to the lack of commercially available assays. <h3>Methods</h3> The Laboratory for Public Health in Alberta offers an in house syphilis PCR assay. It is a multiplex assay targeting both the <i>tpp47</i> and <i>polA1</i> genes and the B2M human DNA control, using TaqMan primers and probes. The assay has been validated for testing lesion swabs. <h3>Results</h3> In concert with the rise in infectious syphilis cases, the lab has seen a 68.6% increase in syphilis test volume in 2018 over that of 2017. The positivity rate increased by 23.8% in 2017 and 264.8% in 2018. Direct testing diagnosed 33% (456/1380) of infectious syphilis cases in 2018. The majority of test requests originate from the two STI clinics, serving the inner city populations of the two major cities in the province. <h3>Conclusion</h3> With the technical difficulty and quality control issues of the treponemal Direct Fluorescent Antibody test (DFA) and darkfield microscopy, molecular assays can play an important role in identifying early syphilis cases, when serology has the lowest sensitivity, thereby assisting public health in their efforts to decrease transmission. <h3>Disclosure</h3> No significant relationships.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".