Why total body scans are a scam

Folks across the country are paying hard cash for total body scans, abdominal aortic aneurysm testing, CAT coronary artery scans and carotid artery evaluations to prevent disease or find important lesions early. It’s a seductive argument, and it’s a scam.

Ordinary patients don’t understand about pre-test probability and positive and negative predictive values. Indeed, all physicians were taught to consider Bayesian theory when ordering diagnostic tests. This is very tough concept for patients to grasp. A critical principle of proper diagnostic testing can be summarized in a single sentence.

If an individual is unlikely to have the medical condition under consideration, then a diagnostic test that yields a positive result is likely to be a false reading.

Here is an illustration demonstrating why patients need to understand this issue. While the forthcoming example is hypothetical, I guarantee that every physician has seen very similar patients in their practices. While the patient presented here has a presumed cardiology issue, every medical specialist and primary care physician can land in the same trap. When this occurs, patients suffer.

A 30-year-old non-smoker sees me in the office with chest pain that is readily relieved with antacids. It is very unlikely to be angina, and probably represents simple heartburn. If I arrange for this person to undergo a cardiac stress test, and the result is positive, then it is much more likely that  the test result is wrong than that the individual has true heart disease. This is not simply my opinion, but a conclusion based upon mathematical and statistical principles. However, try explaining this to a patient with a false positive stress test result. Despite the physician’s reassurance that the test result is erroneous, the patient will likely become anxious and remain unconvinced. Such a patient can easily slide, or be pushed, down a medical cascade that may include cardiac catheterization, or even stenting of a coronary artery that was not responsible for the patient’s symptoms, and should have been left alone.

The key is that diagnostic tests need to be ordered when the patient has a reasonable chance of having the condition under consideration. (If the physician is nearly certain of the disease, then the test may not be needed.) This determination is made on the basis of a careful history and physician examination. When stress tests and various scans are ordered casually by physicians, or requested by patients, then this opens a pathway into a medical labyrinth with no easy way out. Would you prefer to agonize over a false positive test result that pushes you toward medical quicksand, or avoid an unnecessary test in the first place?

Of course, there are rare individuals who have benefited from a scan that was ordered for the wrong reasons. These folks understandably are convinced that the scan saved their lives. These anecdotes, however, which make for potent testimonials, should not change established medical diagnostic principles. Every day, folks become millionaires after purchasing winning lottery tickets. Since nearly 100% of lottery tickets become bookmarks or end up in landfills, we know that this is a poor strategy to accumulate wealth. Should every person undergo a CAT scan of the head every year because it is theoretically possible that a few might benefit by accident? Dumb luck should not be our diagnostic touchstone.

Total body scans, and all of their cousins, are examples of medicine at its worst. It is a commercial enterprise that bypasses sound medical principles and judgment. These entrepreneurs proffer a promise that they knows they cannot fulfill. It’s a scam clad in a white coat. For the majority of their unsuspecting customers, a positive result will be wrong and a negative result will guarantee nothing.  I realize that an ordinary patient will celebrates when his total body scan is negative, but this is not how medicine works.  You can have a normal EKG performed weekly, but this will not prevent a heart attack or exclude significant coronary artery disease.

Still thinking about that cardiac scan being advertised in the newspaper or on television? Do yourself a favor. Buy some snake oil instead. The result will be the same, but you won’t waste nearly as much money and you won’t end up with a stent.

Many patients who have endured a on the medical cascade may feel that they were rescued from certain disaster.  I’d rather rescue folks from the cascade.

Michael Kirsch is a gastroenterologist who blogs at MD Whistleblower.

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  • StockC

    All of what you say is fine in theory until the highly improbable diagnosis turns out to be a reality and the malpractice suits begin to flow. What doctor (or insurance company) wants to stand up to those? Hence, scams or not, multiple unnecessary tests are ordered anyway.

  • http://nostrums.blogspot.com Doc D

    We’ll really be in trouble (physicians and patients) when the lawyers start using total body scans as “standard of care” criteria, as they successfully did for un-indicated plain films.

  • http://www.BocaConciergeDoc.com Steven Reznick MD FACP

    Several times a week ads appear in local papers in South Florida announcing where the imaging van will appear. For $99 you get a carotid ultrasound, and abdominal and pelvic aortic ultrasound and an echocardiogram. There is a smorgasboard of other ala carte items from Cardiac Calcium scoring to nuclear stress tests for a price. Generally the van parks in the lot of a sponsoring religious organization, pharmacy or charitable organization. Anyone who shows up and has cash gets tested. The ads are posted in legitimate newspapers for a fee with no effort of the media to evaluate the appropriateness or professionalism of the organization doing the procedures.

    How is this different than all the non prescription pharmaceutical items and alternative but as yet unproven medical and surgical treatments that consumers can pay for directly?

  • StockC

    Here’s another ‘adverse’ effect of scanning that the typical patient/consumer would never think about. A cardiologist alerted me to this one.

    Suppose you get a Calcium Cardiac scan and come out positive. The scan may indicate positive at a calcium level far less than would concern a cardiologist.

    Now try to get new or higher level of coverage on a life insurance policy. If you answer ‘yes’ on the insurance questionnaire on whether you’ve ever had a positive indicator on a calcium cardiac scan, your policy application will be turned down. If you answer ‘no’, remember that the scan has become part of your permanent medical record. If you answered ‘no’, you may be charged with insurance fraud or may later be denied death benefits on the basis of a tainted application.

    Some medical situations are better not to know about until you absolutely have to.

    • gzuckier

      Excellent point.

  • http://www.Neurology4MRCP.com Osama SM Amin MD, FACP

    It’s all about money. They are running a business and its success should be translated into “the net income!” No matter what clinical statements of guidelines say…
    The practice of medicine is going through a time of turbulent change, and we have many “machines which are doing the work!”

  • Finn

    I have a friend who’s been going to these things instead of finding a new primary care doc after hers died, which concerns me because she has abdominal obesity, a family history of cardiovascular disease, and is obviously unsteady on her feet because (I think) of very weak leg muscles. Her most recent van visit generated an “abnormal results” letter because her HDL was deemed too high. The only good thing is that it scared her enough to finally make an appointment with a new PCP, where they can look at her scam-artist test results in light of her family and medical histories.

  • Marc Gorayeb, MD

    The author’s position was reasonably well argued, until the end. The author’s legitimate concern about false positives led to a concluding diatribe against total body scans that included phrases like “medicine at its worse,” “scam clad in a white coat,” and “snake oil.” It reveals his emotional pre-disposition, which led him to over-reach with his criticism.

    He used the ‘false positives’ argument to improperly argue that the possibility of false negatives made negative tests worthless. If that is true, then
    (1) He should not be doing all those screening colonoscopies.
    (2) The American Cancer Society should retract its study concluding that screening chest CT’s in high risk patients appears to save lives.
    He has failed to provide evidence that negative scans can’t be relied on. The argument fails for that reason.

  • HealthCAre PROF

    WHO CARES???? If people want to spend their hard earned money on scans, so be it. Pro Choice!