"You don't need a prescription to go gluten-free": the scientific self-diagnosis of celiac disease.

We explore the social process of celiac disease diagnosis using fieldwork in the United States with two celiac support groups, interviews, and a virtual ethnography of an online discussion board. Distinguishing between medical diagnosis, self-diagnosis, and scientific self-diagnosis, we examine patients' varied paths to diagnosis and their attempts to legitimize symptoms as celiac disease. Web-based direct-access testing (DAT) permits patients to bypass physician requisition for testing in their diagnostic quest. While such laboratories do not diagnose disease per se, they provide the consumer with the scientific information necessary to self-diagnose. This scientific self-diagnosis grants individuals greater legitimacy for their claims of an illness identity than self-diagnosis alone, but less legitimacy than medical diagnosis. We examine the implications of scientific self-diagnosis for the social construction of diagnosis and professional and lay ways of knowing.