Failure to Thrive

Failure to thrive (FTT) is a medical term used in both pediatric and adult human medicine, as well as veterinary medicine (where it is also referred to as ill thrift).

The term is assumed to refer to an infant or child. In children, it is usually defined in terms of weight, and can be evaluated either by a low weight for the child’s age, or by a low rate of increase in the weight.

Sometimes this diagnosis leads a doctor to perform the sweat test, testing for cystic fibrosis.