Medical Tests & Procedures Archive

What is the test?

A combination of blood test results and the findings seen on a fetal ultrasound can enable doctors to identify pregnancies that are at a higher risk for birth defects. Examples of birth defects that screening can identify are Down syndrome and neural tube defects (brain and spinal cord problems). If the screening tests suggest problems, your doctor might recommend additional tests, such as amniocentesis or chorionic villus sampling, to confirm the findings.

How do I prepare for the test?

Before having this test done, you need to think carefully about what you would do with the results once you have them. The results of these screening tests cannot show for sure whether you have either a healthy fetus or one with a problem. They can only suggest which patients might want to go ahead with further testing.

Could a closer look at your mammogram help guide efforts to prevent heart disease?

Your mammogram could offer a glimpse at more than just the health of your breasts. It may also provide important clues about your heart.

When a radiologist reads a mammogram, she or he sometimes sees little white streaks that look like lines of chalk inside the arteries of your breast. These lines are actually deposits of calcium called arterial calcifications. If you have them, it could mean that you have similar deposits in other arteries inside your body, including those that bring blood to your heart muscle — a known risk factor for heart disease.

Blood testing to detect early cancer may be closer to reality than ever before.

When it comes to most cancers, the sooner they're found, the better. "Identifying cancer in its earlier stages offers improved chances for treating it before it can grow and spread," says Dr. Brian Wolpin, director of the Gastrointestinal Cancer Center at Harvard-affiliated Dana-Farber Cancer Institute.

Unfortunately, there are not reliable tools to screen for most cancers. Examples of effective screening tests that do exist now include colonoscopies that look for polyps and early colorectal cancers, as well as imaging tests like mammograms for early signs of breast cancer and chest CT scans for localized lung cancer among former or current smokers.

Studies of drugs, diets, and devices all come with their own unique set of challenges.

The best way to know if a new medical treatment truly works is with a randomized controlled trial — the "gold standard" of research studies, also known simply as a clinical trial. Volunteers are randomly assigned to receive either the new treatment or the comparison, which may be a placebo (an inactive therapy) or a treatment that's already available.

As the nation's top cause of death, cardiovascular disease has been at the leading edge of evidence generation, says Dr. Robert Yeh, director of the Smith Center for Outcomes Research in Cardiology at Harvard-affiliated Beth Israel Deaconess Medical Center. "We probably have more evidence for cardiovascular treatments than for any other field of medicine," he says. Among the studies with the greatest impact were the clinical trials that heralded new therapies to treat heart attacks. These include clot-dissolving drugs in the 1980s, followed in the 1990s by artery-opening angioplasty procedures, which remain the standard of care today. Stents, the tiny mesh tubes used in these procedures, have also been extensively studied in clinical trials (see "Testing devices: Different dilemmas").

Research we're watching

A new tool to identify people who might be at higher risk for pancreatic cancer could help doctors find cases earlier, when they are most treatable. Researchers from the Harvard T.H. Chan School of Public Health created a risk model that did a better job than current models of finding people at high risk for the disease. It takes into account clinical and genetic factors as well as blood levels of biomarkers (substances that could potentially indicate disease). To test the model researchers used data from four large clinical studies. They applied the tool to 500 known pancreatic cancer patients and more than 1,000 people without cancer. The researchers then assessed how well the tool would have predicted the risk of pancreatic cancer. Pancreatic cancer, which is the third leading cause of cancer death in the United States, is challenging to treat because most people already have advanced disease when they are diagnosed. It's hoped that identifying people who are at high risk will eventually allow doctors to screen these individuals to find cancers when they are smaller and more curable.

Image: Raycat/Getty Images

Cardiac CT angiography is gaining ground as a fast, effective way to diagnose coronary artery disease.

If you experience a short-lived squeezing sensation or discomfort in your chest when you exercise or feel stressed, one possible cause is inadequate blood flow to the heart. Known as stable angina, this condition suggests you have heart disease and may be at risk for a heart attack.

Doctors can use a number of different tests to diagnose (or rule out) inadequate blood flow to the heart muscle. The first step is frequently a type of stress test, which checks the heart's electrical activity, muscle function, or blood flow patterns while the heart is under stress from exercise or medication. Stress tests can identify areas of reduced blood flow, which suggest a narrowing in the artery that supplies that part of the heart.

Ask the doctor

Q. A friend recently had what his doctor called a "3D echocardiogram." How is that different from a standard echocardiogram?

A. All echocardiograms use high-frequency sound waves (ultrasound) to create still and video images of your heart. But there are two different procedures for getting the images and several variations of this common test, which doctors often refer to simply as an echo.

Research we're watching

An increasing number of Americans have a blood abnormality that indicates autoimmunity, which means their immune system has created antibodies that could work against the body's own cells, according to a study published April 7, 2020, in Arthritis and Rheumatology. Autoimmunity can lead to autoimmune diseases such as rheumatoid arthritis or lupus, although the study authors said they didn't look to see whether the prevalence of diagnosed autoimmune diseases also rose during the same period of time.

The researchers found a rise over two decades in the number of people who had positive antinuclear antibody (ANA) blood tests, a signal of autoimmunity. They used blood samples taken from 14,211 people ages 12 and older, as part of the U.S. National Health and Nutrition Examination Survey. In samples taken in the period 1988 to 1991, ANA prevalence was 11%. It rose slightly to 11.5% for the 1999–2004 time period, and to 15.9% in the 2011–2012 period. Comparing differences in gender, race and age, the largest increases in positive ANA tests occurred in men, non-Hispanic whites, adolescents, and adults ages 50 and older.

In the journals

Combining two kinds of biopsies may lead to a more accurate diagnosis of prostate cancer, suggests a study in the March 5, 2020, issue of The New England Journal of Medicine. Researchers from the National Cancer Institute enrolled 2,103 men with prostate abnormalities. Each man had a standard 12-point biopsy and an MRI-targeted biopsy.

With a 12-point biopsy, tissue samples are taken from 12 systematically placed spots on the prostate. An MRI-targeted biopsy uses an MRI image of the prostate to help doctors locate areas where cancer is most highly suspected. Previous research has shown that MRI-targeted biopsies are more accurate than 12-point biopsies. However, even MRIs can miss some tumors.