US health regulators are carrying out investigation into the complaints filed against laboratory and research practices at Theranos Inc. The complaints were filed by the former employees of the blood-testing startup company.

The first complaint was filed in September by a former Theranos lab employee to the Centers for Medicare and Medicaid Services. As per the complaint, the management instructed the lab employees to keep testing patients with the company’s blood-analysis devices despite knowing that the devices had some major stability, precision and accuracy problems.

The second complaint was sent to the Food and Drug Administration (FDA) earlier this month by another ex-employee, who alleged that the study submitted by Theranos last year that get the approval for a herpes test breached several research protocols.

The Wall Street Journal reviewed the copies of both the complaints. A spokeswoman for Theranos, Brooke Buchanan, said the company has not been given any copy of the complaints, so they have no basis to evaluate whatever is mentioned in it.

Theranos strongly claims that all its lab work is accurate and reliable. Recently, Elizabeth Holmes, the company’s founder and chief executive, defended Theranos in public appearances and even pledged to publish peer-reviewed data on its tests.

In response to questions from the Wall Street Journal, last week the company sent its three scientists who had discussion on their work, certain documents and regulatory submissions by Theranos.

Daniel Young, a Theranos vice president and director of its Arizona laboratory, said, “He is not aware of any pressure from upper management to release errors or unreliable results. That goes against everything I know about how Theranos operates”.