Three U.S.-based companies that offer genetic testing services directly to consumers received warning letters from FDA earlier this month for not clearing their tests with the agency. FDA says that the products under question meet the definition of a medical device and therefore need to be approved by FDA before they can be marketed. The companies claim that their tests fall under the category of lab-developed tests, which do not need FDA clearance. One letter went to DNA4Life, which offers a genetic test that claims to predict how a person will respond to more than 120 prescription drugs. Another letter went to Interleukin Genetics for its tests purported to identify increased risk for diabetes, heart attack, conditions related to osteoarthritis, and an “obesity-related genotype for weight loss.” DNA-CardioCheck received the third letter for its test that claims to identify “DNA genetic markers linked to thrombophilia, deep vein thrombosis, cardiovascular disease, and stroke.” FDA’s action comes two years after the agency warned 23andMe to stop marketing its genetic testing service, which provided information on carrier status, health risks, and drug response for more than 250 diseases. 23andMe suspended the service and is now offering a limited number of tests that screen for carrier genes associated with inherited disorders.