Tattoos have long served as fashion statements, and now some Americans are relying on them to warn first responders about important medical conditions.
Medical tattoos are being used to show a person's allergies, chronic diseases and even end-of-life wishes.
But it's unclear if the tattoos carry much legal weight. The American Medical Association doesn't specifically address medical tattoos in its guidelines.
Melissa Boyer, of Nashville, Mich., wore bracelets for years to identify her as a diabetic but now has a 3-inch tattoo on her left forearm that shows she has Type 1 diabetes and is allergic to penicillin and aspirin.
Dr. Saleh Aldasouqi, an endocrinologist at Michigan State University, feels medical tattoos are becoming so popular that the medical profession needs to get involved and help guide their development.