When two longtime patients of Orly Avitzur, medical adviser to Consumers Union, came in back-to-back after undergoing a battery of useless screening tests, she was shaken.

Jen, a 49-year-old homemaker with well-controlled migraines, told Avitzur that her family doctor prescribed them during her annual physical, even though she was feeling great. The tests — arterial imaging of the arms and legs, venous imaging of the legs, cardiac ultrasound, carotid and vertebral artery ultrasounds, and nerve testing of the arms and legs — were done in the doctor’s office by an out-of-town company that travels with its own gear.

Edie, a 50-year-old jewelry designer with sporadic tension headaches and neck pain, had the same set of tests, also done by a mobile unit at her doctor’s office. Although the results were ultimately normal, the whole process caused her considerable anxiety, especially when she was told she would have to go back to the office to go over the results. When the same doctor invited Edie to a Botox party a few days later (a “social” gathering where all the guests get injections), she decided it was time to find another physician.

Too many useless tests

Like Avitzur’s two patients, many people feel uncomfortable questioning tests their doctors advise them to get. Consumer Reports recently surveyed more than 8,000 subscribers without a history of heart disease, and a majority said they had had at least one test recommended only for people with symptoms of heart disease or at very high risk of developing it. Fifty percent said they had undergone an electrocardiogram (EKG), 21 percent had an exercise test and 7 percent received an ultrasound of the carotid arteries. Most said they agreed to the tests without asking about their accuracy or potential complications and without considering what would be done if the results were abnormal. And even more troubling, 87 percent completely or somewhat agreed that it was “better to have a scare that turns out to be nothing than to not get tested at all.”

This is far from the truth. Costs aside, unnecessary testing can lead to interventions — sometimes invasive ones — that can be harmful to your health.

For instance, the U.S. Preventive Services Task Force has concluded that there’s no direct evidence of benefits from an ultrasound to screen the carotid arteries of adults with no symptoms. The results can be misleading and trigger additional unnecessary testing, including invasive arteriograms (which carry a low risk of stroke), and, in a worst-case scenario, even-riskier surgery. The nerve tests that Avitzur’s patients received should be done only if a physician concludes there are symptoms that require that type of investigation. A recent independent review warned that doing the tests improperly could lead to a high rate of misdiagnosis and unnecessary surgery.

How to avoid unneeded tests

- Consider the evidence. Doctors who practice evidence-based medicine consider all the research about a condition and its treatment, including published guidelines, clinical studies and expert reviews, before deciding whether a test is needed. You can, too. The Agency for Healthcare Research and Quality (www.ahrq.gov) and the National Institutes of Health (www.nih.gov) have guidelines specifically written for patients. You can also look up the findings of the Preventive Services Task Force (www.ahrq.gov/clinic/uspstfix.htm) to see if your doctor is following its recommendations. Some of the reviews by the Cochrane Collaboration (www.cochrane.org) are written for patients.

- Follow the money. Be wary of doctors who order tests to be done at their own offices or at freestanding facilities they partly own rather than at independent hospitals or clinics. A recent Medicare law aims to discourage this practice by requiring doctors who refer patients to imaging facilities that they own to notify patients — in writing — that they can get the same services from other providers.

- Get another opinion. If you have doubts, see another doctor. A second opinion can be lifesaving. It is your right as a patient, and your doctor is ethically bound to provide any records you need for this purpose.

Copyright 2011. Consumers Union of United States Inc.