Hi Tx
I just went through similar issues with my DS, who is completing 3rd grade. He did really well in 1st and 2nd grade, but in 3rd grade seemed to be underachieving. His teacher quickly labeled him as unmotivated and did not view him as smart, nevertheless gifted. I knew in my heart of hearts that DS is incredibly smart, but I wasn't sure if I would call him gifted. A friend of mine suggested a full psycho-educational assessment and that is what we did. We met with a psychologist who interviewed me and DH and gathered information from his teachers and physical and occupational therapists (he also has Sensory Integration Disorder). She spent about 6 hours with DS over multiple days, not only doing testing, but getting to know him. In the end, we had the WISC and WIAT, as well as a diagnosis of ADHD and disorder of written expression. (ie Twice Exceptional). We also had a full report describing not only the test results, but describing DS as a student/person. I just got the information last week (which confirmed that he is gifted and underachieving)and I feel the information is going to help me to advocate for him going into 4th grade. I've already met with the principle and the test results were eye opening for her. She now realizes that DS has needs that have not been met at school. Luckily, she is very supportive and plans to work with me on making sure he has the support he needs.

hope this helps.