Sticking Points

Nowadays a blood test usually requires a doctor’s visit, a needle poke in the arm, and a day-long wait for results to come back from a lab. So when Silicon Valley start-up Theranos promised a device that could perform more than a hundred of the most commonly ordered blood tests from just a fingerstick, doctors, patients, and investors were quick to get behind the company. Valued at $9 billion in 2015, the company opened 40 blood testing centers in Walgreen’s stores in Arizona and, in a first step toward more widespread blood testing at patients’ discretion, successfully lobbied for Arizona legislation allowing patients to obtain blood tests without a doctor’s order. But the secretive company came under intense scrutiny after the Wall Street Journal reported last year that the capability and accuracy of its device fell short of company claims. Regulators uncovered standards violations and dangerous lab practices at one of two Theranos laboratories and banned founder and CEO Elizabeth Holmes from operating a blood-testing lab for two years. Theranos compounded its technical setbacks with its lack of transparencyciting trade secretsand not publishing in peer-reviewed journals. The company is now facing a string of lawsuits, including some from its own investors. “It was science fiction. It is still science fiction”, says James H. Nichols, medical director of clinical chemistry at the Vanderbilt University School of Medicine, who says Holmes sold her idea without proof. But the Theranos boom and bust highlights how hard it is to actually do the testing the company promised. “When I was in training”, says Brad Karon of the Mayo Clinic, “everybody was saying, ‘Ten years from now, central lab testing won’t exist.’ That was 20 years ago.” Karon codirects the Mayo Clinic’s point-of-care program and has watched the plodding growth of bedside and fingerstick blood testing. Those with diabetes have been testing their own blood glucose for decades, so why can’t patients yet do fingerstick tests to track a wide spectrum of ailments that have known bloodborne tracers? Cost is part of the reason fingerprick testing hasn’t taken off. It’s hard to compete with highly efficient, automated, central laboratory tests. But stubborn challenges also lie in sampling and analysis. Small drops collected from fingersticks have more variable contents than the larger quantities drawn from veins. And, despite the development of new devices that analyze a handful of different blood markers from microliter volumes, quantifying hundreds of markers at once from such tiny amounts of blood will require new strategies. While Theranos pushed the vision of fingerstick blood testing further than it had ever gone, other innovators in both blood sampling and multianalyte testing are stepping in to try and realize it.