The problem of medical identity theft is on the rise, according to Pam Dixon, who heads a non-profit group called the World Privacy Forum that helps victims of identity theft. Between 250,000 and 500,000 people have their medical identities stolen each year, Dixon says. Most of the perpetrators are "people working in the healthcare sector," such as billing or housecleaning staff or clerical workers at large hospitals who have access to confidential patient information such as Social Security and health insurance policy numbers, she said.