Theranos, Inc., a beleaguered, multi-billion-dollar startup developing blood testing technology, is now under investigation by two federal agencies, according to a report in the Wall Street Journal.

Complaints from former employees sparked the two investigations, one by the Food and Drug Administration and the other by the Centers for Medicare and Medicaid Services (CMS). According to the WSJ, those complaints laid out concerns about breached research protocols as well as severe accuracy problems with the company’s blood tests.

Theranos gained prominence and drew skepticism earlier this year with claims that it could perform a multitude of medical tests with just a few drops of blood. While previous media reports have also raised questions about the accuracy of the fingerprick-based tests, the new report outlines concerns over the only blood test that has so far received FDA approval, a herpes test.

A spokeswoman for Theranos, Brooke Buchanan, told the WSJ that the company hasn’t seen “a copy of any alleged complaint, so we have no basis to evaluate what is in it or even if a complaint has been filed.”

In September, a former employee filed a complaint with the CMS alleging that Theranos managers were aware of inaccuracies with the company’s testing devices, called Edison machines, since 2013. The employee alleged that Edison devices would spit out wildly different results for the same patient. For example, in a test for thyroid hormone, which helps regulate the body’s metabolism, the Edison’s results would swing between showing a patient had hypothyroidism (too little hormone) to hyperthyroidism (too much hormone), the ex-employee said.

The former employee alleged that the company ignored the problems and pressured employees to carry on without any fixes. The same employee also accused the company of improperly diluting blood samples.

In a complaint to the FDA, another ex-employee alleged that Theranos didn’t have the necessary technology assembled to study the efficacy of its herpes test when the experiments began. And, during the experiments, the company underreported to the FDA how often the Edison devices broke down. The herpes test, which later received FDA approval, was also modified part-way through the experiments, the former employee alleged.

Buchanan told the WSJ that the former employee that filed the FDA complaint was “uninformed” and “disgruntled.” She added that the FDA-approval was “hard earned and the product of significant efforts by dozens of exemplary scientists and engineers—honest, hardworking, highly qualified individuals.”

After the initial media reports of problems at Theranos in October, CEO and founder Elizabeth Holmes promised to release data on the blood tests. Buchanan told the WSJ that such data were not ready and declined to give a target date for their release.