I'm so glad to read these special notes on places that advertise gluten-free menus and would like to add a really fabulous experience at Guapo's in Shirlington. They were incredibly attentive and asked the chef for specific items that qualify as safe. They served grilled chicken, black beans (they make them there without "flavoring"), steamed veggies and I even had good luck with the house-made tortillas and salsa which I was a little reluctant to try despite the assurance of the chef.
I also wanted to share another safe place, at least for me, Bangkok 54 on Columbia Pike. Ask for Nack, one of the owners, and explain your situation - she is wonderful. Their rice noodle, steamed and curry dishes have been safe for me, so far - they make their curries from scratch. I recommend making a reservation, though, it gets busy.
Thanks to everyone who posts reviews!!!:-)