Doctors (and the medical tests they use) don't know everything. It was just a very short 60 years ago that the polio vaccine was developed. Heck, bloodletting was still in use in the 20th century! Listen to your body...it knows...
Just so you're aware...there is a big difference between losing weight on the scale and actually losing fat. It is physically impossible to lose 5 pounds of fat in 4 days. Whenever you see quick weight loss it almost always water. To lose one pound of fat in one day you need to run a 3500 calorie deficit...meaning if you eat 1500 calories, you need to burn 5000!
The thing is she mentioned she is getting better gluten-free. That is not going to happen if the diagnosis is wrong. Sure there might be additional issues going on, but a positive response is a great diagnostic tool. I just read an article that someone posted from an MD in the child thread where the doctor even stated using it as the simplest and very effective diagnostic tool for celiac.
A positive response as a diagnostic tool! Not only does that make perfect sense but it is used all the time. In fact, the true mechanism of action--how it works--in most pharmaceutical drugs in unknown. In a very simplified way, it is hit and miss process. Rogaine (rx to treat baldness) was originally develope to treat hypertension. And if it's not necessarily diagnostic, it's certainly treatment.
There are good docs and not-so-good-docs...and it's not always intentional. For too many years we put doctors on pedestals and assumed they were always right and we did what they told us to do. Unfortunately, or fortunately (!) the human body is a very complex thing.
In my very humble opinion, 100 years from now we may very well look back on on medical knowledge and think we were in the dark ages in 2011. I also believe that as patients, we need to take an active role in our care...which is exactly what you've done. Trust your own instincts. Listen to your body.