“An example would be a patient who comes in at age 55, having had pain for a year all over her body, and the doctor doesn’t see too much [on X-rays and in blood tests] and says, well, it’s just your arthritis,” says Dr. Goldenberg, who specializes in the treatment of fibromyalgia.

“Because a person just has some typical osteoarthritis that you get over age 50, but in fact, osteoarthritis doesn’t cause people to say that I hurt all over my body all the time,” he adds.

Additionally, in medical school, many doctors are taught the maxim, “When you hear hoofbeats, think horses, not zebras.” In other words, go with the simplest, most common medical explanation rather than attributing symptoms to a rarer condition.

A patient who comes in with all-over aches in January is more likely to have the flu than lupus, but that won’t always be the case. And if you’re a medical zebra, but your doctor is used to looking for horses, you may be misdiagnosed.

Here, again, is where preparation can pay off. As soon as your doctor gives you a diagnosis, hit the library and the Internet. Check reliable references to find out what symptoms are typical for the condition you’ve been told that you have.

6) You didn’t get a physical exam.

Fewer doctors are performing regular physical exams on their patients, where they watch, listen to, touch and manipulate a patient’s body looking for clues that something is amiss, and the lack of such information can lead to mistakes.

When a rheumatologist touches your knuckles, for example, joints that are red, swollen, hot and soft may point to an inflammatory form of arthritis, like RA; while joints that are cool and hard on physical exam may be more indicative of OA.

Ghaith Mitri, MD, chief of the Division of Rheumatology and Immunology at the University of Florida College of Medicine in Jacksonville, says he recently treated a man in his 40s who had been diagnosed by multiple doctors with a variety of conditions. One physician finally lumped the man’s perplexing symptoms into a diagnosis of dermatomyositis, an autoimmune disease that causes extreme muscle weakness and a skin rash.

Dr. Mitri had doubts. He had asked the patient, who was a brawny guy, to hold his arms out while he tried to push them down. “I could almost climb on top of [his arms,] he was so strong,” Dr. Mitri says.

Because the patient was moving and speaking unusually slowly, however, Dr. Mitri ordered a blood test to check his patient’s thyroid, a gland that controls how the body uses energy. The result: very low thyroid function.

After a few months of taking synthetic thyroid hormone, the patient returned to normal health.