The company says it has taken 'comprehensive corrective measures.'
Theranos loses its COO as it seeks to improve quality
With a criminal investigation under way, the company is making changes at the top.
WSJ: Walgreens is waiting for answers about Theranos blood tests
Theranos has worked with Walgreens to perform blood tests since 2013, but with questions raised about its "fingerprick" technology the partnership is up in the air
