P144 Does use of a diagnostic certainty score at TB cohort review improve culture confirmation of active tuberculosis?

<h3>Background</h3> Diagnostic confirmation of TB disease is central to high-quality TB care. It ensures that patients receive the correct treatment, (for TB and conditions that may be mistaken for it) and also allows drug susceptibility testing. However, in 2021 only 61% of TB diagnoses in England were confirmed by positive culture. Improving this is a key objective for the UKHSA/NHSE TB Action Plan, with a specific target of 80% of pulmonary cases being culture-confirmed. Since 2017 in North Central London TB service we have reviewed the evidence for a patient’s TB diagnosis at the quarterly Cohort Review, with a diagnostic ‘level of certainty’ being recorded for each case discussed. We explored how patterns of diagnostic confirmation have changed since this was introduced. <h3>Methods</h3> We collated diagnostic codes recorded at cohort review for the period 2017–22. When this was recorded as ‘Definite TB’, we cross-checked results with data on TB cultures and TB PCR results to confirm whether this was based on positive culture or PCR. Site of disease data were also included from 2018. <h3>Results</h3> Data on 1311 TB notifications between 2017 and 2022 were available. Over this time-period we observed an improvement in proportion with culture confirmation from 59% in 2017 to 79% in 2022 (figure 1) (p &lt; 0.001). In addition, TB diagnosis was confirmed by TB PCR in an increasing proportion of culture-negative cases – rising from 3% of culture negative cases in 2017 to 20% (64 cases) in 2021. Since 2018, 84% of pulmonary TB cases were confirmed by TB culture and 53% of extra-pulmonary cases. <h3>Conclusions</h3> The introduction of a diagnostic certainty score as part of the cohort review process has been followed by a significant improvement in confirmation of TB disease in NCL TB service. Culture confirmation of pulmonary cases now reaches the UKHSA target of &gt;80%. Regular discussion of diagnostic confirmation rates at cohort review may have had the effect of changing practice and reducing the proportion of cases treated empirically. We suggest that inclusion of culture confirmation information within the cohort review process is an effective way of evaluating and improving practice.