Multi-billion dollar health startup Theranos tried to kill a report questioning how well its 'revolutionary' blood test actually works

Theranos, the $9 billion healthcare startup, went to lengths to try to kill a damning report in the Wall Street Journal.

The paper spoke to former Theranos employees, their families, a number of experts, the company's lawyers, and reviewed the medical records of a number of patients that had taken a Theranos blood test. They told the WSJ that - in late 2014, at least - the company didn't use its own high-tech test on the majority of blood samples, and relied on methods developed by other companies.

The WSJ says Theranos fought the newspaper throughout its investigation, especially when it came to patients who offered up their medical records and the healthcare professionals who interpreted them. The Wall Street Journal wrote:

After those people spoke to the Journal, Theranos visited some of them and asked them to sign prepared statements that said the Journal mischaracterized their comments. Two did and one refused."

Theranos also threatened to sue the wife of British biochemist Dr Ian Gibbons, who was hired by Holmes in 2005, according to The Wall Street Journal report. He produced 23 patents in collaboration with other scientists, with Holmes listed as a co-inventor on 19 of them. But Dr Gibbons later told his wife Rochelle that "nothing was working." His wife explained this to the WSJ, adding that Dr Gibbons had committed suicide in May 2013.

After that, Theranos reached out, the WSJ said:

After Dr. Gibbons's widow spoke to a Journal reporter, a lawyer representing Theranos sent her a letter threatening to sue her if she continued to make "false statements" about Ms. Holmes and disclose confidential information. Ms. Gibbons owns Theranos shares that she inherited from her husband.

Business Insider contacted Theranos for comment about allegations that it attempted to suppress The Wall Street Journal's investigation, and about the claims within it. We will update this article once we hear back.

Holmes' company has claimed that its lab machines - named "Edison," after the famous inventor - were able to carry out the full range of blood tests on a few small drops of blood collected by pricking a patient's finger.

But the WSJ found that the company actually does the majority of its tests using traditional machines bought from companies like Siemens. Most of the tests Theranos conducted in December 2014 were done using larger samples of blood collected from veins on patients arms, according to The Wall Street Journal.

Theranos also diluted 60 small samples collected using the pinprick method and tested them with normal machines, only using the combination of its famous blood collection method and its own Edison machines for 15 tests, the investigation claims.

Employees also expressed concern that not only were tests with diluted samples proving inaccurate, but that Theranos' signature 'pinprick' tests was revealing different results to traditional methods, according to the report.

The Wall Street Journal's report refers to instances in 2014, so it's not clear whether Theranos' technology works to full effect now. Investors have backed the company with $88 million in total, and the company is valued at $9 billion.