The top 5 tests you probably don't need

Some health screenings may do more harm than good.

Certain health screenings, such as colonoscopies and cholesterol checks, are wise preventive measures. But other common tests may be unnecessary.

"I think we're doing too much over-screening," says geriatrician Dr. Suzanne Salamon, an instructor at Harvard Medical School. "This leads to the discovery of too many harmless variations of normal body parts, which then lead to expensive, anxiety-producing, and often painful further overtesting and unnecessary procedures."

Here are the top five tests our experts say you can probably forgo.

1 Electrocardiogram

In this test, also known as an ECG (or EKG), technicians place electrodes on your chest to check for abnormalities in your heart's electrical activity. But for healthy people without heart disease symptoms or risk factors such as high blood pressure, smoking, or diabetes, the test is not recommended. The U.S. Preventive Services Task Force says there's no evidence that routine ECG screening offers any benefits, and that it might pose some risks if further unnecessary tests are done. "Even though an ECG is extremely safe and relatively inexpensive, the cumulative costs add up if everyone gets one," says cardiologist Dr. Deepak Bhatt, a professor at Harvard Medical School and editor
in chief of the Harvard Heart Letter.

2 Whole-body CT scan

This test uses x-ray computed tomography (CT) to look inside your body for early warning signs of conditions such as heart disease, aneurysms, cancer, osteoporosis, and lung disease. But these scans cost hundreds of dollars, aren't usually covered by insurance, and involve radiation exposure. The FDA says there's no scientific evidence that whole-body scans of individuals without symptoms provide more benefit than harm. "These pick up all kinds of 'incidentalomas' that lead to needless anxiety and expensive screenings, as well as excessive radiation. I don't think doctors order them. I think people see ads in magazines and sign up for them," says Dr. Salamon. While it's possible that technological improvements could make such scans a good idea someday, that's not the case today.

3 Coronary calcium score

This test uses CT to scan your arteries for signs of calcium deposits that put you at risk for heart attacks. Dr. Bhatt says studies have shown that it may be useful when used in patients who are at intermediate risk, according to traditional risk factors, since abnormal results can push a person into a high-risk group. "Perhaps knowing that they have a high calcium score would encourage them to lose weight or stay on their statin, for example, though the data supporting this are mixed," he says. But because of radiation risk and the risk of additional unnecessary tests and procedures, he recommends against this test for routine screening, as does the American Heart Association.

4 Chest screening

The American Lung Association recommends low-dose CT to detect early signs of lung cancer for current or former heavy smokers ages 55 to 74 with a smoking history of at least 30 pack-years. But if you're not in this group, you should not have a routine screening: the risk from radiation exposure and potential unnecessary follow-up testing is not worth the small chance of benefit.

5 TB skin test

A skin test can detect if you're been infected with the tuberculosis (TB) bacteria. But if your doctor suggests a routine screening, make sure to ask why. The TB skin test is recommended only for people who have spent time with a person with TB; who have a weakened immune system from HIV or another medical problem; who have TB symptoms such as fever, cough, and weight loss; who use illegal drugs; or who are from or work in countries where TB is common. (Russia is one example.) If you don't fall within those categories, a skin test is likely an unnecessary expense.

But what if my doctor recommends it?

"That is what makes medicine not just a science, but also an art. Ultimately, you have to trust your doctor's judgment," says Dr. Bhatt. If it is a risky or expensive test or procedure and you feel apprehensive, you might consider a second opinion.