An untold number of people have been rejected for medical coverage because insurance companies are using huge, commercially available prescription databases to screen out applicants based on their drug purchases. Privacy and consumer advocates warn that the information can easily be misinterpreted or knowingly misused. The practice is adding another layer of anxiety to a marketplace that many consumers already find baffling, reports Business Week. The obstacle primarily confronts people seeking individual health insurance, not those covered under an employer's plan.