Elizabeth Holmes defends herself and her company Theranos at WSJLive 2015. WSJ Two former employees of the blood-testing startup Theranos are accusing the company of deleting quality-control data of its proprietary machines and cherry-picking data when comparing those machines with traditional lab machines, according to a report published Sunday by The Wall Street Journal.

The first incident, according to The Journal, involved a blood test ordered in 2013 for a patient using the company's proprietary Edison lab machine. The lab worker assigned to the test reportedly found problems that indicted accuracy problems with the device. When the lab worker told superiors, the report said, an employee in research and development came to the lab and deleted the data.

In the second incident cited by The Journal's John Carreyrou, an employee sent an email to CEO Elizabeth Holmes in 2014 suggesting the company "cherry-picked" data when comparing the Edison machines to traditional blood-testing machines to make the machines look more accurate.

From the report:

For one test, the device’s accuracy rate increased sharply after some information was deleted and manipulated, the employee wrote. Edison machines also allegedly failed daily quality-control checks often.

Theranos representative Brooke Buchanan told The Journal she didn't believe the first incident ever happened. In the second incident, Buchanan put the blame on the employee, who she said was too inexperienced to "make these types of comments."

This isn't the first time Theranos has run into trouble in the past few months.

Earlier this month, The Journal reported that regulators for the Food and Drug Administration and Centers for Medicare and Medicaid Services were investigating two separate complaints by former employees of the startup.

The first complaint accused the company of instructing employees to test patients' blood using Theranos' devices even though there was evidence of "major stability, precision, and accuracy" issues.

The second complaint said a study submitted by Theranos last year for a herpes test was extremely problematic because of improper research protocols.

The blood-testing company known for its finger-prick testing technology came under fire in October after The Journal raised questions about the accuracy of the company's test results. In October, the FDA also released a series of concerns about the company after visiting Theranos' labs.

Read the full Wall Street Journal report here.