FIG 4.

Serial testing with IGRAs reveals underlying phenotypes. The persistently positive pattern is seen in individuals who are repeatedly IGRA positive for a long time. Unstable conversion refers to individuals who convert their IGRA result from negative to positive and then revert again to negativity. Stable conversion refers to individuals who convert their IGRA result and stay converted, at least in the short term. Persistently negative refers to individuals who stay repeatedly IGRA negative for a long time. (Reproduced from reference 88 by permission from Macmillan Publishers Ltd.)