Medical Tests & Procedures Archive

Research we're watching

Taking supplements that contain high levels of biotin (vitamin B₇) can lead to falsely low results on a blood test used to detect heart attacks, according to an FDA warning issued late last year.

For adults, the recommended dietary allowance (RDA) for biotin is 0.03 milligrams (mg), which is easily obtained through a healthy, varied diet. Many multivitamins and prenatal vitamins contain far more biotin than the RDA. And some supplements — particularly those marketed to improve hair, nails, and skin — contain 20 mg, or nearly 650 times the RDA.

On call

Q. I'm 80 and no longer do colon cancer screening. However, I recently noticed some bleeding from my rectum. Does that change my need for a colonoscopy?

A. Screening for a disease means the person has no symptoms. Since you now have rectal bleeding, a colonoscopy would be considered not a screening test, but a diagnostic test. Whether you have it now or wait to see if more bleeding occurs depends upon many factors. The most important question is whether anything found on the colonoscopy will lead to treatment that improves your quality of life.

Several new technologies and medications that may benefit the heart are moving into cardiology care.

As regular readers of the Heart Letter know, our features tend to focus on lifestyle advice and currently available therapies for heart disease. As the new decade begins, we're also looking to the future. Editor in Chief Dr. Deepak L. Bhatt selected five promising new developments in cardiovascular research that you may be hearing more about in the coming years.

1. Digital stethoscopes

First developed more than 200 years ago, the instrument doctors use to listen to the heart and lungs has undergone some high-tech improvements in recent years. The latest digital stethoscopes feature specialized microphones and sensors that filter, buffer, and amplify sounds from the heart. The sounds are then converted to a digital signal and sent wirelessly to a smartphone, where the patterns can be visualized and further analyzed. Some models are so sensitive they can detect turbulent blood flow in the arteries of the heart, possibly enabling doctors to detect coronary artery disease. Studies assessing that potential use are currently under way.

They often lead to follow-up appointments and more testing.

Modern medical imaging saves lives: it can find a blocked artery, a bulging blood vessel, or a suspicious mass. But many times, an x-ray, CT scan, MRI scan, or ultrasound exam looking for one kind of problem can reveal an anomaly that's unrelated and unexpected. Such incidental findings can lead to more testing, more medical bills, and a great deal of anxiety.

"Frequently radiologists will point out something and say it's probably benign, but recommend an MRI. Once you've been told something might be abnormal, you might feel nervous until you know what it is," says Dr. Suzanne Salamon, associate chief of gerontology at Harvard-affiliated Beth Israel Deaconess Medical Center.

The once-a-year appointment can reveal vital health information for both you and your doctor.

It's usually covered by your health insurance, it doesn't take much time, and it's a great way to learn about your present and future health.

While men often call it the yearly physical, the annual ritual is better named a wellness visit or preventive health appointment. Whatever you call it, men should still have one every year as it remains an important part of primary care, according to Dr. Asaf Bitton, executive director of Ariadne Labs and primary care physician at Harvard-affiliated Brigham and Women's Hospital.

Here is what men need to know to minimize discomfort of a prostate biopsy and get the best results.

News briefs

About half of all people in the United States living with a diagnosis of HIV (human immunodeficiency virus) are age 50 or older. But new data from the CDC suggest most Americans have never been tested for the virus (which causes AIDS, the late-stage phase of HIV infection). According to the June 28, 2019, Morbidity and Mortality Weekly Report, less than 40% of people in the United States have had an HIV test, even though the CDC recommends routine testing at least once for everyone age 13 to 64. The CDC notes that older adults sometimes aren't tested for HIV because they don't consider themselves at risk for infection or because their health care providers don't offer them the test. Older people may also mistake late-stage HIV symptoms, such as weight loss and frequent illness, for signs of normal aging. Those symptoms occur because HIV attacks the body's immune system. But a delay in diagnosis allows the virus to cause more damage. That's unfortunate, since medications can keep the infection from progressing.

If you haven't had an HIV test, talk to your doctor about whether it's right for you, no matter your age, especially if you are sexually active or have had more than one sex partner.

On call

Q. I suddenly developed low back pain for the first time. My doctor said I did not need an x-ray or other imaging test. Is that normal and are there any situations when a test would be needed?

A. Yes, your doctor is following the current guidelines. Unless you have other symptoms in addition to low back pain, an x-ray, CT scan, or MRI is not likely to be helpful. But it could cause unnecessary worry while waiting for the results and cost you some money if it's not covered by your health insurance. In addition, many people have "false-positive" results in which an abnormality is detected but turns out to be harmless.

Your blood pressure is one of the best ways to measure overall health and possible risk factors. Do you know your numbers?

There are many important health markers: cholesterol levels, blood sugar levels, weight — to name but a few. But men often fail to use one of the most important: blood pressure.

"Your blood pressure is one of the easiest and simplest measurements and can tell you so much about your current and possible future health," says Dr. Randall Zusman, director of the division of hypertension for Harvard-affiliated Massachusetts General Hospital's Corrigan Minehan Heart Center. "Yet most people don't know their number or check it on a regular basis, so they may not be doing everything they need to lower their risk of a heart attack or stroke."

In the journals

A new study found that a simple blood test can detect beta-amyloid protein buildup in a person's brain years before Alzheimer's disease symptoms appear. The results were published online Aug. 1, 2019, by the journal Neurology.

High amounts of beta-amyloid can clump together and form plaques on the brain, which is strongly associated with Alzheimer's disease. Other research has found that amyloid plaques can appear as early as 20 years before the first sign of Alzheimer's symptoms, such as cognitive decline and memory loss.