The answer isn't simple, and it depends on the type of insurance, the state you live in, and many other factors. Typically, the organization sponsoring the clinical trial covers what are considered the "research costs," which include everything associated with the running of the trial: data collection and management, the time spent by the research physician and nursing staff, and the tests performed as part of the trial. There is, however, a whole set of additional costs known as "patient care costs," which usually include transportation to and from the trial, as well as blood tests and other tests not directly related to the trial. The sponsoring organization often doesn't cover these.

There's good news, though: At the urging of the National Cancer Institute, a growing number of states have passed legislation requiring health plans to pay the cost of routine medical care that patients receive while participating in a clinical trial.

This doesn't mean, however, that insurance pays all the costs. Clinical trials often involve additional tests, medications, and medical appointments that don't fall into any of these categories. Some health insurers and managed care providers will decide if they'll cover patient care costs based on whether they consider the trial treatment to be "experimental" or "investigational" -- in which case they'll say no -- or "established" -- in which case they may cover it. Disputes often must be negotiated between the research sponsor and the insurance company.

Medicare does reimburse patient care costs for its members who participate in a clinical trial to diagnose or treat cancer. Information about Medicare coverage of clinical trials is available at www.medicare.gov (click on the Search Tool called "Find Out What Medicare Covers" and, on the next screen, choose the coverage topics "Clinical Trials" for inpatients, outpatients, or both).