On Sunday, former Apple executive Jean-Louis Gassée wrote about his personal experience using Theranos, the controversial blood-testing startup that has been valued at $9 billion by private investors. Specifically, he claimed that certain test results he received from the company were well out of line with what he had received from Stanford Hospital’s Hematology Lab, and that subsequent efforts to contact Theranos CEO Elizabeth Holmes were met with silence.
Gassée is not the only person to have this sort of experience.
Fortune recently was contacted by a senior technology executive in Silicon Valley who years ago was diagnosed and treated for thyroid cancer. (We have agreed to keep his identity confidential in the interest of privacy.) Last fall, he had blood drawn by finger stick at a local Walgreens (WBA) store, which then was sent to Theranos for analysis.
One of the results he received—for something called “free T4,” which helps track thyroid function and disease—was a whopping 308% higher than any of his prior test results since being treated. Theranos marked the result as “high.”
Worried, the executive chose to have the same test done three days later at Stanford Hospital, which produced a result well within his normal range. Fortune has viewed both sets of test results.
The executive says that he called a Theranos customer service number and spoke to someone who took his contact information and promised a call back. It never happened. When the executive shared this lack of reply with his internist, he says the internist was dumbfounded, having had the exact same experience with Theranos.
“I’m very fortunate to have great medical care and have been very diligent in tracking my results over a period of years,” the executive explains. “But what if I was newly-treated, or had an overworked or young doctor who didn’t react by realizing that this result was so far out of line? This isn’t about a startup not doing a grocery delivery properly. It’s about people’s health, people’s lives.”
Theranos does not publish error rates for the free T4 test. It is not clear whether the executive’s blood was analyzed using one of the company’s proprietary Edison machines or with a more conventional machine purchased from a third party, though Holmes said today at an industry conference that all finger-stick tests are analyzed using the company’s own equipment.
A Theranos spokesperson says the company logs and tracks inbound calls from ordering physicians. It is common in the laboratory industry for ordering physicians to request reruns, the spokesperson added, and Theranos performs them. The company is, like its peers, federally regulated to track customer complaints. There are few in number, the spokesperson said.
Founded in 2003, Theranos rose to prominence in recent years for technology that allowed its blood diagnostic tests to be performed with a fraction—as little as 1/1000th—of the blood necessary for a conventional test. A series of Wall Street Journal reports published last week raised serious questions about the validity of the technology. The company has since responded.
Previously: Theranos’ board: Plenty of political connections, little relevant expertise
Subscribe to Data Sheet, Fortune’s daily newsletter on the business of technology.
