You've been told you need surgery.

You've been reading about that Navy surgeon who allegedly botched so many operations. So you well may say, "I'd like another opinion."

What if you wind up with two conflicting opinions? The first doctor has said, "Do it." The second says, "Don't."

You have two choices. You can decide one opinion is more credible and go along with it. Or you can seek still another opinion -- or opinions.

Many persons do consider other opinions before letting anyone cut into some crucial area. A few years ago a medically well-informed friend of mine consulted several neurologists and neurosurgeons before deciding to ignore the first opinion he had been given: one to undergo a delicate brain operation to try to correct the cause of a recent seizure.

My friend, and the neurologist whose advice he finally decided to take, decided the seizure probably had been brought on by unusual stress and an infection rather than a brain anomaly that indeed existed, generally without symptoms, but would be highly risky to fix.

My friend has been fine since.

That is no assurance that he will stay fine or that he made the right decision. Medicine offers us no more guarantees than anything else in life. We have to try to get the best counsel we can and play the odds, as doctors do every day in deciding what to tell patients.

Most health plans that cover second opinions -- Medicare Part B (doctor bill coverage) and many Washington area Blue Cross-Blue Shield contracts, for examples -- will also cover a third opinion.

Medicare covers further opinions on any subject in the same way that it covers any consultation, but, unless you're in the hospital, you must have Part B coverage, the part of Medicare where you pay the government a quarterly premium.

The typical Blue Cross-Blue Shield or commercial insurance second-opinion plan typically pays for second or third opinions for only a specified list of procedures.

What if your operation isn't on the list? Except for the more extensive forms of breast surgery, cancer surgery is not on this area's Blue Cross-Blue Shield list. But cancer doctors and cancer patients often must decide whether to have surgery or rely on chemotherapy or other treatment.

You can still get another opinion, and have it covered, just by having a doctor send you to another doctor for a consultation. It will then be covered in the same way as any other required medical visit, subject to whatever limits or co-payments by you that are part of your health plan.

But also face the fact: if you want a large number of opinions, you may have to start paying for them. My friend's health plan covered all his consultations; he just sent in the bills. But some plans might balk at some point.

Where should you go to get a third or further opinion?

You have a choice here, too. You can go to another surgeon or specialist competent in, say, cancer treatment, if that is the issue.

Or you can go to an arbiter: a primary physician, usually a family practitioner or internist, accustomed to refereeing conflicting advice and trying to decide what's best for this particular patient.

If you're fortunate -- or wise, also well enough covered or financially fixed -- you may already have a reliable personal doctor. I certainly wouldn't want to make any decision about important surgery without talking to my own doctor, who's been seeing me every now and then for several years and knows my medical history, much of my personal history and many of my quirks.

A possible third choice if you're highly uneasy: you can go to both the third surgeon or specialist and also a personal M.D. as referee.

The decision in some cases can be agonizing. You may not get two but three or more sets of advice, each advocating a different treatment.

Often, however, a consensus develops. Or at least a consensus among those physicians in whom you have the most confidence.