Book traversal links for 1.3 The TB infection cascade of care
Identifying, testing, evaluating and treating people with TB infection is a multistep process that has been termed the TB infection cascade of care (15). The cascade is described in detail in Chapter 4. In brief, it comprises several steps that may involve health care personnel in different locations. Losses can occur at every step of the TB infection cascade. A systematic review showed that these losses resulted in less than 20% of those eligible for TPT completing their course of medication (15). Importantly, under field conditions, 70–80% of the losses occurred before the initiation of TPT. Testing for TB infection can also be a barrier to the uptake of TPT, for various reasons including the unavailability of test materials, inadequate personnel to administer and interpret the tests, or the need for multiple visits. In summary, although testing for TB infection is not mandatory for the highest risk groups, it can provide important benefits to individuals and programmes, to target action to those more likely to benefit from it, avoid unnecessary treatment and enhance confidence of both provider and the recipient. However, important practical and programmatic challenges remain that limit access to TB infection testing. The impact of these challenges on the cascade of care must be considered at local level, and steps taken to resolve identified challenges.