5 medical tests to think twice about

You may assume your doc is being thorough when she runs a gazillion tests, but there's a downside to being too proactive. New studies show that many people don't benefit from costly screening tests that come with pitfalls such as false positives and excessive radiation. So doctors tend to do fewer of them. Here are some tests you may be able to skip (for a full list, go to choosingwisely.org.)

Health.com: 27 Mistakes Healthy People Make

Bone-density test

Aside from those who are at high risk for weak bones, women should wait until they are 65 to have their bone density measured. Younger women are unlikely to have outright osteoporosis, and while the scan may detect mild bone loss (osteopenia), the risk of a fracture is low and the drugs that may be prescribed to treat this condition carry side effects and haven't proved to be highly beneficial in these cases.

CT scan or MRI, for headaches

Most of the time a careful medical history and a neurological exam (e.g., measuring reflexes) can diagnose the problem. And CT scans involve a hefty dose of radiation.

Health.com: 11 Surprising Headache Triggers

EKG or exercise stress test

Hooking up to an electrocardiogram (EKG) and/or taking an exercise stress test makes sense if you have symptoms of heart disease or are at high risk, but those at low risk who are just looking for reassurance may get inaccurate results that can lead to further testing and overtreatment with drugs.

Imaging for lower-back pain

You don't want to skip an X-ray, CT scan or MRI if there are signs of a severe problem (a history of cancer, fever or pain that lasts several weeks), but lower-back pain often gets better in about a month.

Health.com: 5 Quick Ways to Stop Back Pain

PET/CT for cancer screening in healthy people

The likelihood of finding cancer in healthy adults using these screening methods is extremely low, according to the Society of Nuclear Medicine and Molecular Imaging.

This article originally appeared on Health.com.

More from Health.com:

The Best and Worst Foods for Pain

19 Signs Your Thyroid Isn’t Working Right

21 Reasons Why You’re Losing Your Hair