Just Google "interpreting AChR test." You'll find answers and videos by doctors. A positive AChR result indicates the presence of the acetylcholine antibody, which is associated with one type of Myasthenia Gravis. The provider is requesting an additional test by radioimmunoassay. The AChR test is very definitive. Follow the advice of whatever provider requested the test, If that's not a neurologist, I would recommend finding one.