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Should You Get a Thyroid Test? It's Not Clear

There's not enough evidence to advise for or against routine thyroid tests, a top-level panel says.
Image: A technician inserts a needle into a vein of a person as donating blood in Indianapolis
Should people without symptoms get a blood tests for abnormal thyroid levels? A new study says - maybe, maybe not.Michael Conroy / AP

It’s often a standard blood test for middle-aged women: A blood check to see if the thyroid’s working right. But is it worthwhile if someone doesn’t have any symptoms? It’s too soon to say, federal advisers report.

The U.S. Preventive Services Task Force, which advises the government on major health matters, looked at the evidence, and found there are not enough studies to say whether the benefits of looking at thyroid hormones outweigh the risks and the trouble.

Thyroid trouble is fairly common. About 5 percent of U.S. women and 3 percent of men have an underactive thyroid, known as hypothyroidism, but have no symptoms. Untreated, low thyroid function can lead to heart disease and bone loss. In pregnant women, it can cause premature birth or cause the baby to have a lower-than-average IQ.

Only about 2 percent of people with abnormal thyroid hormone levels develop symptoms. Symptoms can be vague, such as weight gain, feeling cold and hair loss. And it’s an easily treated problem – a generically available hormone called levothyroxine will normalize blood levels. The USPSTF found that 71 million people got levothyroxine in 2010.

Overactive thyroid function, known as hyperthyroidism, is found in less than 1 percent of the population. It can cause weight loss and a rapid heart rate.

The USPSTF found little risk to overscreening and didn’t consider the costs. The bottom line: More evidence is needed to advise for or against it, they report in the Annals of Internal Medicine.


-- Maggie Fox