Elizabeth Holmes, founder and CEO of Theranos.
CNBC—NBCU Photo Bank via Getty Images
October 22, 2015 11:15 AM EDT

The blood test company Theranos has published a lengthy response to last week’s Wall Street Journal articles that questioned the effectiveness of the company’s tests.

“The stories say or imply many things that are simply wrong,” Theranos said in its rebuttal.

A key point of contention is the importance of the “Edison” technology, which the Journal describes as “the lab instrument developed as the linchipin of [Theranos’] strategy” to be able to perform blood tests on small samples taken with a finger-prick. Theranos says it has invented more than just the Edison tech. “In fact, ‘Edison’ is an earlier version of just one of our proprietary devices used as part of Theranos proprietary technologies,” the company wrote.

Another issue centers on how many of Theranos’ blood tests are actually conducted using a finger-prick instead of a traditional needle. The company says that 57% of its guests had labs done on finger-stick samples in the fourth quarter of 2014, a figure that has “evolved” over time. The company has expanded the number of tests it offers and has been “working to transition to an FDA framework,” which is why it says some of its tests are carried out using regular needles. In the Journal article, the newspaper notes that a sentence saying “many” of Theranos tests only require a few drops of blood was removed in recent months and that Theranos’ lawyer said the change was made for marketing accuracy. However, Theranos says the lawyer was misquoted and the company changes its website regularly.

Theranos also disputed a claim made by anonymous “lab experts” in the Journal story that finger-pricked blood samples are can be less pure than those drawn from a vein. The company says it generates validation data proving equivalence between capillary and venous lab results before submitting tests to the FDA.

The company also went to great lengths to explain how its protocols for proficiency testing, the process by which blood testing companies prove that their processes are accurate, adheres to regulations. Theranos said it never heard about a complaint an employee sent to New York state’s public-health lab under an alias from any regulators, which was mentioned in the Journal article.

Finally, Theranos questions the validity of many of the sources used in the Journal story. The company says anonymous former employees quoted in the story didn’t understand Theranos’ technology and anonymous lab experts are likely Theranos’ competitors. “From his very first interactions with Theranos, the reporter made abundantly clear that he considered Theranos to be a target to be taken down, and not simply the subject of an objective news story,” the company concluded.

The Journal hasn’t responded to Theranos’ Thursday statement, but issued a response Wednesday to CEO Elizabeth Holmes’ comments comparing the publication to a tabloid: “We note that Ms. Holmes sought to challenge the reliability of our sources, but it remains the fact that she doesn’t know from whom the information for our articles was gathered,” the Journal said. “We assure her and our readers that our sources were well positioned to know the information they provided about Theranos, and they were vetted before publication.”

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