On treasure maps, "X" always marks the spot. But in the operating room, when physicians mark patients' bodies in preparation for surgery, an "X" often isn't good enough. Differences in how they indicate which area is to be operated on cause thousands of medical mistakes every year, and states are starting to take measures to reduce those errors.

Known as "wrong-site" or "wrong-side" surgeries, these procedures involve a doctor's operating on the wrong part of a patient's body-- the wrong knee, the wrong elbow or, in more extreme cases, the wrong part of the spine or brain. Medical experts estimate that about 4,000 wrong-site surgeries occur in the United States annually. A great many are simply the result of a failure to mark the body part meant for surgery. But even when doctors do mark the spot, personal differences in marking techniques can have tremendous consequences. Surgeons may use an "X" to mean either "operate here" or "not here." And writing "not this wrist" becomes problematic if the "not" is smudged or rubbed off.

For about a decade, medical professional groups have focused on reducing wrong-site errors by having physicians mark patients clearly. In 1998, the American Academy of Orthopaedic Surgeons endorsed a "Sign Your Site" program, encouraging doctors to initial the spot intended for operation. In 2004, the Joint Commission on Accreditation of Healthcare Organizations took steps to standardize patient markings. The commission, which accredits about 80 percent of the nation's hospitals, instituted a requirement that physicians mark surgical sites with either a "yes" or their initials.

States have also begun enacting measures to address wrong-site surgeries. The New York State Health Department has recommended guidelines for health care institutions to cut down on these types of mistakes. And the Florida Board of Medicine in 2001 instituted $10,000 fines and other penalties for doctors who perform wrong-site procedures. State law in California identifies the anesthesiologist as the person responsible for correctly marking a patient. But in other states, determining that responsibility can be confusing.

Even simply getting a handle on how many of these errors are occurring can be a problem. More than 25 states have mandatory reporting laws that require hospitals to disclose medical errors. But officials believe these incidents are still grossly underreported. A handful of states have adopted a standardized list of medical mistakes, known as "never events," that experts say should not ever occur. At the top of this list (which also includes events such as leaving a foreign object in a patient after surgery) is wrong-site surgery. In 2003, Minnesota became the first state to adopt a never- events law, which requires hospitals to disclose publicly the occurrence of any event on the list. Indiana, New Jersey, Connecticut and Illinois have followed with similar regulations.

Utah has gone a step further. Health officials there actually conducted a survey of physicians to see how they marked patients for surgery. They discovered that even when doctors did identify the intended operative spot, the inconsistencies among those marks were dangerously confusing. "We found up to 12 different ways of marking patients," says Iola Thraen, patient safety director for the health department. "They were using X's, smiley faces, stickers, patient initials, their own initials, their signatures, you name it." This past December, the health department announced a new protocol requiring every licensed physician in Utah to write "yes" on the spot meant for surgery. Officials hope the measure will bridge the gap for institutions not accredited by JCAHO. Also, by targeting individual physicians, as opposed to institutions, Utah officials predict greater success in reducing wrong-site errors.

Experts say that's the key to reducing these errors. "The answer is not to keep punishing organizations or exhorting people to do better," says Dr. Paul Schyve, JCAHO's senior vice president. "The answer is to change the processes the doctors are working in." By focusing on getting physicians to mark patients in a clear, standardized way, states can help ensure that patients who undergo surgery are all right--or left, as the case may be.