Editor's Note

Are Quarterly Blood Tests Needed?

A call for regular blood tests incites discussion on patient empowerment.

By Jeanette McCarthy, MPH, PhD

Mark Cuban, the businessman, Shark Tank cohost, and Dallas Mavericks team owner, had some in the medical establishment crying foul in April. He advocated that any of his approximately 3 million Twitter followers who can afford it should establish their own personal health profiles by getting regular blood tests for as many things as possible, even when they are not sick. The controversy stems from the fact that some blood tests are not very reliable, especially as screening tools in healthy individuals, and can result in false positives that may lead to unnecessary interventions.

As a spectator to the volley of arguments, I couldn’t help noticing how Cuban’s comments were aligned with both precision medicine, whose roots are in understanding the molecular basis of disease, and participatory medicine, where patients are more engaged in managing their health and more involved in their health care. In fact, we’ve celebrated some super-quantified selfers who have taken a similar approach. For example, astrophysicist Larry Smarr from the University of California, San Diego, charted his laboratory measures and other health parameters over time and self-diagnosed his preclinical Crohn’s disease. Similarly, geneticist Michael Snyder from Stanford University School of Medicine quantified his genome, proteome, metabolome, and other omes and observed how his body responded to infection at the molecular level.

There is tremendous value in understanding the molecular profiles of healthy individuals. The Google Baseline study, a collaboration between Google and Duke and Stanford Universities, is one of several efforts under way to map a healthy human body. This study highlights the value of longitudinal collections of biospecimens from healthy individuals for research. The ability to measure cholesterol levels in a healthy population, for example, allowed us to associate cholesterol levels with cardiovascular disease risk. In the age of so many omics, these specimen collections and associated clinical data are invaluable for understanding the molecular etiology of disease. In Biobanks and the Future of Genome Research, you’ll learn about some of the large biobanking efforts around the United States and how they’re being used to find new disease biomarkers. It’s a great way to donate your body to science without having to die first!

So, was Cuban’s advice off the mark? Since I’m an advocate for patient empowerment and ownership of health data, I would say no. But I believe we need to find a way to collect, share, and use these and other health indexes responsibly. Consumers should be educated about the value and limitations of current laboratory tests they might undertake in the name of establishing health profiles. If we’re concerned that patients may self-diagnose and suffer psychological consequences or undergo unnecessary procedures based on knowing their lab values, we need to facilitate data sharing and encourage consultation with their doctors.

There are a lot of parallel conversations going on about ostensibly healthy individuals having access to their genomic data. Some feel the information may have no value or, worse, be dangerous for the general population. I would stop short of recommending that everyone get his or her genome sequenced, but if someone wants that information, I think he or she should be able to receive it in a responsible manner. This means educating both consumers and healthcare providers about the strengths and limitations of the technology and about the importance of both nature and nurture in disease.

Although individuals may benefit from knowing their genetic potential, the real value of collecting genomic data on healthy individuals is for research. In our story Genes That Protect You From Disease, you’ll learn how studying individuals who are healthy despite carrying a deleterious mutation (so-called resilient individuals) can teach us about the factors that protect us from diseases. In Will Genetic Testing Make You Anxious?, you’ll learn about another type of resilience: how some people seem innately resilient to bad news, including bad news about their genetic predisposition.

I’ve had my genome sequenced but have not had a comprehensive analysis of my blood except for a standard metabolic profile ordered during a routine doctor’s visit. I’m tempted to do so, but I’m not quite sure what I would want to measure. I imagine one day that question will be informed by our genomes. Because I carry a variant in a gene that may cause biotinidase deficiency, maybe I should have my biotin levels measured. Since I carry a celiac disease–predisposing genotype but remain unaffected (and also given that I passed it on to my kids, who weren’t so lucky), perhaps a routine celiac panel makes sense. If I had a strong predisposition to diabetes, more routine glucose monitoring might be prudent.

I can see how knowing my genetic predisposition may call for personalized monitoring strategies. Although the temptation for quantifying all possible health indexes is there, I’m not sure what I would do with that information. For now, I might start with my own personal biobank.