Blood is a great communicator. Monitoring levels of hormones, proteins, and other substances in our blood can give us important information about everything from cancer to heart disease. Now blood tests are being marketed directly to consumers to help them read the signs of illness or aging. But buyer beware, experts warn. Scientists don't yet understand what many blood "biomarkers" really tell us about our health, they caution, and pricey tests that claim to help decipher their code may promise more than they can deliver.
Last month, Austin-based Biophysical Corp. launched a test called BiophysicalYou that screens for 60 biomarkers that may reflect our body's aging process. The test, which can be ordered through the company's website for $1,495, evaluates whether standard biomarkers like cholesterol and glucose that are routinely part of a physical exam fall within normal ranges. It also measures other markers such as those associated with inflammation, which may indicate the presence of some sort of disease. Marketing materials promoting the test say that by evaluating these biomarkers you may be able determine if you're aging prematurely and make adjustments to your diet or exercise routines, for example, to try to correct the problem.
The test is a variation on the company's flagship Biophysical250, which analyzes 250 biomarkers in an effort to detect early-stage diseases or medical conditions. About 1,000 people have taken the $3,400 test since it was launched two years ago, according to the company. When someone orders either test, the firm dispatches a nurse to draw approximately two tablespoons of blood, which is sent to the company's Austin lab for analysis. (The test is also available at Canyon Ranch spas.) Within a few weeks, Biophysical sends the consumer a hefty report that analyzes how the results stack up against the norm. Biophysical encourages consumers to discuss their report with their personal physician; in some states, a doctor actually may have to order the test and/or receive the results.
Blood biomarker tests provide more concrete evidence of actual medical problems than genetic tests, which can only measure the likelihood someone will eventually get sick, says Biophysical founder and CEO Mark Chandler. "Blood biomarkers are indicators of a disease process that is already at work," he says. About 7 percent of test takers' results point to a problem that should be discussed right away with a doctor, he says, and an additional 15 percent of tests result in readings that indicate warning signs for possible problems down the road.
Doubts. Experts outside the company agree that biomarkers have a vital role to play in patient care, but many express concern that tests like those offered by Biophysical create unrealistic expectations. "We don't even know what many of these biomarkers mean, let alone how to treat the patient if they're high," says James Januzzi, director of the cardiac intensive care unit at Massachusetts General Hospital, who is researching the use of biomarkers to diagnose and treat heart failure. By his count, only about 10 percent of the 250 biomarkers in the Biophysical250 test are clearly associated with a particular medical disorder. Many others, he says, can't be reliably linked to any specific ailment.
Some blood biomarkers clearly have therapeutic value in helping practitioners diagnose and treat disease: Cholesterol tests assess heart disease, glucose tests monitor diabetes, and the prostate-specific antigen, or PSA, test can help diagnose prostate cancer. But for many tests, the connection to disease is not nearly as clear. Biomarkers that indicate inflammation in the body are a good example. Inflammation occurs when the immune system is activated in response to disease or infection, among other things. Rising levels of inflammatory biomarkers like interleukins or tumor necrosis factors could indicate myriad medical problems, and a biomarker test can't distinguish one such problem from another. "Can we tell you whether inflammation means you have gingivitis or inflamed arteries? No, that would require additional testing," concedes Chandler.
Independent experts are concerned about the additional diagnostic testing that Biophysical reports may generate. By analyzing up to 250 biomarkers, they cast such wide nets that, for any given person, some results will almost certainly fall outside normal ranges, says Sharyl Nass, study director for the Institute of Medicine report, "Cancer Biomarkers: The Promises and Challenges of Improving Detection and Treatment," published earlier this year. "That will lead to additional testing and expense and invasive procedures," she says. "Without some evidence that it actually makes a difference, there's no reason to do that."
Many people would be interested in a test that allowed them to detect cancer at its earliest stage when it is most treatable. But of the 46 cancer biomarkers on the Biophysical250, only the PSA test is specific enough for routine use as a screening tool for people at average risk for cancer, says Len Lichtenfeld, deputy chief medical officer for the American Cancer Society. Other biomarker tests can't reliably identify a particular cancer in most people. A higher-than-normal level of the marker known as cancer antigen 125, for example, may be reason to perform surgery if a woman is at high risk for ovarian cancer. But for a woman whose family history or genetic makeup suggests she has average risk, the message—and what one should do about it—is unclear, says Lichtenfeld. In such a case, he wonders, "If this woman's test comes back minimally elevated, where do you go from there?" Sometimes, knowledge isn't necessarily power.