Medical Tests & Procedures Archive

News briefs

A warning for people who take the dietary supplement biotin (vitamin B7): the FDA says taking too much of the vitamin may interfere with the results of some lab tests. Biotin is often included in multivitamins, prenatal vitamins, and dietary supplements marketed to improve nails, hair, and skin. While there's no recommended dietary allowance established for biotin, the adequate intake value is 30 micrograms per day for people ages 19 or older and for pregnant teens and women. But biotin supplements may contain up to 650 times the adequate intake. The FDA warns that taking too much biotin can interfere with lab tests, such as hormone tests and tests for markers of heart attacks (like troponin). An inaccurate lab result can have dangerous consequences. For example, the FDA reports that one person taking high levels of biotin died after a falsely low troponin test result. The FDA also notes it's seeing an increase in reports of biotin interference in lab work. The bottom line: Always tell your doctor which supplements you're taking. And remember, most people can get enough biotin from a healthy diet that includes seeds, nuts, meat, fish, eggs, and certain vegetables (such as spinach and broccoli).

Research we're watching

Going home the same day after having an angioplasty not only is safe, it may save the health care system an average of more than $5,000 per person, a new study reports.

Every year, some 600,000 people in the United States undergo coronary angioplasty, a minimally invasive procedure to open a narrowed heart artery. About half are so-called elective angioplasties, which are done on people with predictable but worrisome chest pain (stable angina).

Ask the doctor

Q. My doctor wants to measure my ejection fraction. What does that mean, and what should I expect?

A. With every heartbeat, your heart contracts and relaxes. During the contraction, the heart's main pumping chamber, the left ventricle, ejects blood out to the rest of the body. When your heart relaxes, the ventricle refills with blood. The ejection fraction is the percentage of blood leaving the chamber each time it contracts.

Research we're watching

Picture this: One day, you may be able to use your smartphone camera to detect atrial fibrillation. Also known as afib, the irregular heart rhythm raises the risk of stroke. New research suggests that the technique, which relies on a special app, is almost as accurate as an FDA-approved mobile electrocardiogram.

Here's how it works: You place your index finger on the smartphone camera, which uses the camera's light to detect changes in your pulse. The app algorithm then uses that information to determine whether your pulse is steady and regular (normal rhythm) or fast and irregular (afib).

Ask the doctor

 Image: © patrickheagney/Getty Images

Q. Is it possible to have a heart attack even if you don't have any blockages in your heart's arteries?

A. Yes, you can. Doctors refer to heart attacks without blocked arteries as MINOCA, which stands for myocardial infarction (that is, heart attack) with non-obstructive coronary arteries. When it occurs, people may experience typical heart attack symptoms, such as chest pressure or pain in the center of the chest (or the arms, jaw, neck, or stomach) and trouble breathing. They also have elevated blood levels of a protein called troponin, a marker of heart damage that is used to diagnose a heart attack. But the next test — a special x-ray of the heart's arteries called an angiogram — shows no evidence of a significant buildup of fatty plaque blocking any of the heart's arteries.

Ask the doctors

 Image: © scibak/Getty Images

Q. I just saw that the FDA issued a warning on vaginal laser procedures. Are these procedures dangerous?

A. More study of these laser procedures is needed to conclusively determine if they're safe and effective for vaginal conditions. If you're considering one of these procedures, have a detailed conversation with your doctor about traditional medical therapies as well as the pros and cons of laser treatments. The FDA issued a warning on July 30 about energy devices (laser therapy).

Research we're watching

A test that screens for human papillomavirus (HPV) beat a commonly used cervical cancer screening method in detecting changes that may lead to cervical cancer, according to a study published July 3 in The Journal of the American Medical Association. Some 19,000 women were screened for cervical cancer using either the HPV test or a more traditional and commonly used liquid-based cytology test. After 48 months, all the women were tested again using both tests. Researchers found that among women who'd had a normal initial screening, those who'd been screened with the HPV test had significantly fewer grade 3 or worse precancerous cervical changes at the final testing compared with those screened with liquid-based cytology.

In response, the U.S Preventive Services Task Force now recommends either HPV testing only once every five years or liquid-based cytology once every three years for women ages 30 to 65.

According to a new guideline, testing should start at age 45, but not everyone needs to have a colonoscopy. Other tests are also available.

Colon cancer screenings for people at average risk for the disease should start at age 45 instead of 50, says a new guideline from the American Cancer Society (ACS).

The change to the screening recommendation, which was published in the May 30 issue of CA: A Cancer Journal for Clinicians, was made because the number of colon cancer cases among adults under age 55 rose 51% from 1994 to 2014, and colon cancer deaths in this age group rose 11% from 2005 to 2015.

Ask the doctor

 Image: © andresr/Getty Images

Q. I was recently diagnosed with aortic stenosis after my doctor heard a slight heart murmur and referred me for an echocardiogram. I don't have any symptoms, so the cardio­logist recommended that I get periodic echocardiograms to monitor the condition. Is there anything else I can — or should — do?

A. Aortic stenosis — also called aortic valve stenosis — occurs when the one-way valve inside the heart's largest vessel, the aorta, stiffens and becomes clogged with calcium deposits. As a result, the valve doesn't open as easily. During a heartbeat, as the heart's main pumping chamber (the left ventricle) contracts, pressure builds up behind the aortic valve. This creates the turbulent blood flow that a doctor can hear through a stethoscope.

Certain tests involve small amounts of radiation. Here's some perspective on the benefits and risks.

Cardiologists have many options for visualizing the heart, some of which involve exposure to radiation. Used appropriately, these tests can identify possibly life-threatening conditions, such as dangerous heart artery blockages. In recent years, the accuracy of many of these noninvasive tests has increased. They're also being used with increasing frequency.

Because ionizing radiation can damage cells, potentially raising the risk of cancer, experts acknowledge that imaging tests that involve radiation should be used judiciously. Earlier this year, the American College of Cardiology published a consensus statement on the best practices for safe and effective use of radiation in cardiac imaging tests.