"While we are disappointed by CMS' decision, we take these matters very seriously and are committed to fully resolving all outstanding issues," Holmes said in a statement.
Theranos was once praised for its fast, less-invasive blood testing technology, but the company has found itself in the spotlight after media reports raised questions about the accuracy of its proprietary tests.
The company has suffered a series of blows, which began with a high-profile exposé from The Wall Street Journal last year that called the company's underlying technology into question.
The higher number of abnormal test results, researchers wrote, 'can have negative consequences for medicine in the form of extra testing, additional patient visits to clinics/hospitals, and added doctor services.'