Take a look at these headlines: Minnesota doctors remove the healthy kidney from a cancer patient while leaving the diseased one behind; California doctors remove the appendix from the wrong patient; one of the most experienced surgeons in a Boston, Massachusetts hospital operates on the wrong side of a patient.

No one knows exactly how many surgical errors happen each year in the United States; most states don’t require hospitals to report them. But the above three examples all happened within the past year, and experts believe many more mistakes never get publicized.

Of course, it’s hard to prevent surgical errors; after all, you’re anesthetized. But before the surgery, there are steps you can take to lower the chances that you’ll be the next headline. The first rule: ask lots of questions. “You need to be that thorn in their side,” said Dr. Samuel Seiden, an anesthesiologist who’s co-author of a study on surgical errors. “You will catch things. You might also frustrate the nurses, but you have to look out for yourself.” Here are some other tips:

1. Check out your doctor and hospital

Specifically, ask your doctor how many times he or she has done this procedure, and compare that with other physicians.

You can check out the hospital by going to HealthGrades or The Leapfrog Group, which rank hospitals by specialty. (For example, you can find good places to get hip surgery in Topeka, Kansas, or to have a baby in New York.) The U.S. Department of Health and Human Services has detailed information about procedures performed at different hospitals.

2. Tell everyone who you are and why you’re having surgery.

You may feel like an idiot, but tell all the nurses and doctors your name, your date of birth, and what surgery you’re having (for example, “I’m John Smith, I was born 10/21/70, and I’m having arthroscopic surgery on my left knee.”). This can help prevent you receiving a surgery intended for someone down the hall. (Of course, if your name really is John Smith, you might want to give your address, too).

3. Make sure your doctor initials your site

The American Academy of Orthopaedic Surgeons urges its members to sign their initials directly on the site before surgery (shown in the group’s public service ads, like the one pictured above). Make sure your surgeon — not somebody else — does the signing and that it’s in the right place.

For more tips, check out my column at cnn.com/health