The release of You Can See Everything, a film documenting the final weeks before Elizabeth Holmes went to prison in 2023, has returned the disgraced entrepreneur and her failed blood-testing company, Theranos, to public attention. But while the film revisits the downfall of one of biotechnology’s most notorious start-ups, researchers and entrepreneurs are still pursuing the technological ambition that helped make it famous: performing numerous diagnostic tests using only a few drops of blood.
During the 2010s, Theranos attracted investors with claims that its Edison device could conduct hundreds of tests from a finger prick, potentially reducing the need for conventional blood collection and laboratory procedures. The company’s rise was followed by a dramatic collapse after its technology failed to deliver what had been promised. US federal juries later ruled that Theranos had misled financial supporters about its device’s capabilities, and two executives, including Holmes, received prison sentences of more than a decade.
The consequences extended beyond the company itself. Paul Yager, a bioengineer and diagnostics developer at the University of Washington in Seattle, says Theranos left “a crater in the whole field of monitoring and diagnostics”. For years after its collapse, researchers proposing new blood-testing technologies encountered the same question from prospective investors and colleagues: “How is what you’re trying to do different from what Theranos did?”
The question remains relevant as a new generation of companies develops diagnostic systems intended to make testing faster, cheaper and more convenient. Dena Marrinucci, co-founder of Truvian Health, a diagnostics company in San Diego, California, says the industry must establish credibility through demonstrated performance rather than ambitious claims. “Trust in diagnostics has to be earned through evidence and not promises,” she says.
The technical difficulties behind Theranos’s failure illustrate why that distinction matters. Conventional diagnostic testing commonly requires several vials of blood drawn from a vein in the arm, providing a sufficiently large and consistent sample to measure substances ranging from electrolytes to hormones. The results can help clinicians diagnose and monitor a range of health conditions.
Theranos claimed its Edison platform could perform hundreds of tests using just a few drops obtained through a finger prick. Behind the scenes, however, the company struggled to make the system work as advertised. It instead diluted patient samples and used conventional testing machines manufactured by other companies, sometimes producing skewed measurements.
Eric Olson, founder of Babson Diagnostics in Austin, Texas, says several factors probably contributed to the failure, including the company’s reliance on finger-prick blood rather than samples taken from an arm vein. Collecting blood from a fingertip can introduce contamination. Squeezing the finger to obtain droplets can damage blood cells as they emerge from the skin, releasing cellular debris that may distort measurements.
Small sample volumes create another problem. Yager explains that measuring glucose, which is abundant in the bloodstream, can be feasible with a tiny droplet. Other substances that indicate disease, including viral particles associated with HIV infection, may circulate at much lower concentrations. A few microlitres of blood may contain too little of such a biomarker for a device to detect reliably.
Yet the demand for accessible diagnostics has sustained efforts to overcome these limitations. Yager says rapid blood monitoring could be particularly valuable for people living in rural areas far from centralised laboratories, as well as older and disabled people who have difficulty travelling to medical appointments.
Over the past year, he says, blood-testing start-ups have multiplied so quickly that he has struggled to keep track of them. He believes part of the commercial expansion is driven by ultra-rich individuals and social-media influencers encouraging apparently healthy consumers to pay for biomarker tests in the hope of extending their lifespans. Many of these tests, he says, have not yet been validated.
Some companies are concentrating on improving existing collection methods rather than attempting to eliminate their limitations. Babson Diagnostics’ BetterWay blood-testing service uses a specialised device to standardise finger-prick collection, extracting six to 12 drops while reducing the likelihood of cell damage.
Truvian has developed TruVerus, a device that the company says can measure 40 biomarkers using about eight drops of blood. For now, however, the company obtains those droplets from a tube containing blood drawn from a vein in the arm. Marrinucci says the device, which is not yet commercially available, can produce results in less than 25 minutes, allowing patients to discuss their findings with physicians quickly.
Other researchers are seeking to remove the need for bulky diagnostic equipment altogether. Yager, chief scientific officer at UbiDX, a start-up in Redmond, Washington, is working with colleagues on disposable tests for blood and other fluids. Their approach uses paper microfluidics, in which specialised paper draws fluid through chemical testing zones without requiring pumps or laboratory robots.
The need for simpler equipment is illustrated by Cue Health, a San Diego-based company that developed an at-home molecular test reader for COVID-19 using nasal swabs. The company filed for bankruptcy in 2024. Among the difficulties it faced, Yager says, was competition from inexpensive over-the-counter COVID-19 tests that relied on simple strips rather than larger devices requiring space and servicing.
Holmes’s former circle is also pursuing new diagnostic technology. According to You Can See Everything, her fiancé, Billy Evans, is developing a device through a new company, Haemanthus, intended to capture “thousands of biomarkers simultaneously”. The technology is reported to rely on Raman spectroscopy, which uses laser light to measure molecular concentrations in blood, urine and saliva.
Jürgen Popp, a chemist at the University of Jena in Germany, describes Raman spectroscopy as a “well-established analytical technique with significant potential for medical diagnostics”. But he cautions that its application must be supported by “rigorous validation and independent clinical evidence”.
