BTG3 and juvenile idiopathic arthritis: However, even if the test is used more sensibly to address specific questions such as: "does this child with a rash and fever have lupus?" or "does this child with a swollen knee have juvenile idiopathic arthritis (JIA)?", or "is this child with JIA going to develop uveitis?" we would argue that the ANA test is simply not accurate enough to answer even these questions.