The “say what?” study last month describing the disturbing frequency of errors in medical diagnoses has prompted much navel-gazing in many quarters.

One story, in KaiserHealthNews.org (KHN), quoted Leslie Michelson, who heads Private Health Management, a company that charges substantial fees for helping patients figure out what’s wrong with them, as saying he wasn’t surprised.

Too often his company has found that its clients don’t have the condition originally diagnosed; sometimes, the diagnosis is correct, but the treatment is not.

Many patients can avoid paying the steep rates Michelson charges, he said, if they would be more assertive about their medical care. His book, “The Patient’s Playbook: How to Save Your Life and the Lives of Those You Love,” directs people how to research doctors and conditions, and how to cultivate trusted family and friends as backups when you’re seriously ill. Here are excerpts of his interview with KHN about how to navigate the health system and avoid diagnostic errors.

What is diagnostic error and how common is it?

Someone being treated for the wrong cancer, for a disease they don’t have, … [for] back pain when [it’s not clear] whether the cause of the pain is a structural issue, a neurologic issue, an auto-immune condition or something else. And yet they’re going in with an intervention. It’s particularly painful with respect to cancers. When people are treated for the wrong cancer, they’re generally getting treatment that is totally ineffective. They get none of the benefit of the intervention, but all the side effects.

What are the three most important things a person can do to try to avoid a diagnostic error?

If you get a … significant diagnosis, it’s always important to see a physician with the exact expertise in what you have, particularly if it’s a rare condition.

Second is to get a second opinion. …You’re talking about determining an expensive, potentially complicated treatment program. If diagnosis is not measured twice – independently confirmed by a second pathologist – why engage in this entire potentially multi-year, multi-modality intervention unless you know exactly?

The third piece is to become an educated consumer. For all sorts of reasons, all of us are acculturated to be passive when it comes to our health, particularly when we’re sick. Figure out how to summon the courage and develop the confidence to partner with your physician. There are terrific resources online that everyone can use to understand whether their diagnosis is accurate.

Can you name some?

One of the best ones is the National Comprehensive Cancer Network. It’s a group of 26 major cancer centers that … have developed treatment protocols for all the major cancers. You can find out the symptoms, the treatments and what indices will result in a diagnosis that’s accurate. Another great resource is something called Expertscape. They’ve taken all the medical articles over the past decades, organized them by disease and identified the authors of those articles. All you need to do is put in the name of that diagnosis, put in your zip code, put in a radius of how many miles you are prepared to travel, push search and it will identify for you the physicians who have done the most prominent research on that condition.

Reading your book can make one paranoid. What if my doctor is wrong? At what level should seek a second opinion?

Americans are fabulous consumers. We’re good at harnessing information. If it’s a significant issue that is being diagnosed, get a second opinion from an expert in exactly that condition. Even if it’s not, if that little nagging gut instinct says to you “this isn’t right,” act on it.

Are there other groups that help someone who doesn’t have tens of thousands to spend on private services like your firm’s?

Yes, there are so many resources [from] disease-specific foundations. You can get tremendous pamphlets, resources and recommendations for physicians. All of them are out there awaiting an email from you, a phone call from you.

Isn’t there a risk, if patients follow your recommendations, that it would lead to additional tests and procedures that may not make a difference in their treatment or outcome, but would add costs to the patients and society?

No. Part of the reason we have overtesting or overtreatment problems in the U.S. is because of the structure of the reimbursement system. Physicians generally get paid more to do more. The second cause is patients that are too passive. When patients learn how to use the resources online to learn about their diseases and the fundamental importance of getting to experts in their precise condition, my experience is they will have the shortest line between the presentation of symptoms, the development of definitive diagnoses and the implementation of effective treatment plans. A lot of unnecessary costs – and the best estimates are that 30 percent of all health care spending is either unnecessary or counterproductive – are because patients aren’t going to specialists they need to.