You Can See Everything chronicles the final weeks before disgraced entrepreneur Elizabeth Holmes went to prison in 2023. Since its US release last week, the film has thrust Holmes and her failed blood-testing start-up, Theranos, back into the spotlight. For the biotechnology industry, however, the spectre of Theranos never went away.

Blood, sweat and tears in biotech — the Theranos story

More than a decade after the company’s spectacular collapse, a new generation of diagnostics firms still grapples with the fallout. During the 2010s, Theranos said that its device could run hundreds of tests on only a few drops of blood, drastically reducing the amount of fluid needed for routine diagnostics. The company’s success soared as investors backed the technology, but US federal juries later ruled that Theranos had misled those financial supporters about its device’s capabilities, and two of its executives, including Holmes, were sentenced to more than a decade in prison.

Today, health-tech companies are still developing devices similar to the ones that Theranos aspired to make. The firms say that Theranos’s demise underscored the importance of transparency in their pursuit. “Trust in diagnostics has to be earned through evidence and not promises,” says Dena Marrinucci, co-founder of Truvian Health, a diagnostics company in San Diego, California.

Theranos left “a crater in the whole field of monitoring and diagnostics”, says Paul Yager, a bioengineer and diagnostics developer at the University of Washington in Seattle. For years after its collapse, he says, researchers pitching blood-testing technologies faced the same opening question in every meeting: “How is what you’re trying to do different from what Theranos did?”

Bad blood

Standard diagnostic tests, which can measure everything from the levels of basic minerals — or electrolytes — to hormones in the blood, typically require several vials of fluid drawn from a person’s arm to ensure a large, homogeneous sample. The results can be used to diagnose and track various health conditions.

Theranos, which was based in Palo Alto, California, claimed that its Edison device could execute hundreds of diagnostic tests on just a few drops of blood from a finger prick. But behind the scenes, the company was having a hard time making the platform work as advertised, and instead resorted to diluting patient samples and running them on standard blood-testing machines from other companies, in some cases producing skewed measurements.

Although many factors probably contributed to Theranos’s failures, says Eric Olson, founder of Babson Diagnostics in Austin, Texas, one of them was using blood from a finger prick rather than an arm vein. This introduces the potential for contamination of the sample. For example, sometimes squeezing the fingertip to extract blood droplets can cause blood cells to burst as they emerge from the skin, leaking debris into samples and causing erroneous measurements.

Tiny blood volumes also run into a statistics problem, Yager says. Measuring an abundant molecule in the blood, such as glucose, requires only a small droplet because a person’s bloodstream is chock-full of the sugar. But many other molecules that are biomarkers of disease, such as viral particles from an HIV infection, circulate at much lower concentrations. In a few microlitres of blood from a finger prick, those molecules might barely register on a device’s detector.

Working around limitations

Despite those challenges, the biotechnology industry hasn’t given up on Theranos’s goal. That is because making rapid blood monitoring more accessible remains an urgent problem, Yager says, especially for people who live in rural areas that are far from centralized laboratories, and for older and disabled people who struggle to travel to medical appointments.

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Over the past year in particular, Yager says, the number of blood-testing start-ups has multiplied so quickly that he has struggled to keep track of them. He thinks that the commercial boom is being driven in large part by ultra-rich people and social-media influencers who are urging seemingly-healthy consumers to pay for biomarker tests, many of which have not yet been validated, in a bid to extend their lifespan.

Rather than trying to defy the limitations that Theranos struggled with, some companies are attempting to engineer their way around them. Olson says that BetterWay, the blood-testing service at Babson Diagnostics, has standardized the typical finger-prick collection method with a specialized device that extracts 6–12 drops of blood and reduces the likelihood of cell damage.