DIAGNOSING TB: THE BEGINNING OF A NEW ERA?

Combating the spread and reducing the rates of resistant tuberculosis (TB) requires diagnostic accuracy. Both under and over diagnosis have enormous consequences for patients and society. We need a diagnostic test that has extremely high precision—a balance of sensitivity and specificity. In this issue, Taylor and colleagues from Newcastle, describe the theoretical effects, based upon data from 120 children, of following the NICE guidelines for diagnosis of TB that emphasise the use of QuantiFERON-TB Gold. Although they estimate that 85% fewer children would have been diagnosed with latent TB infection, and spared chemoprophylaxis, two children would have been missed. In an accompanying perspective, Drs Shingadia and Novelli comment on the new diagnostic tests for TB, conflicting data that have emerged about these tests, and the complexities of making an accurate diagnosis. Until we have more experience with these new tests, or they are improved, the final diagnosis of TB in a patient will be based upon laboratory assessment, risk …