Theranos responds to the FDA's criticisms of its technology

On Tuesday the FDA released documents related to its visit to Theranos' labs, and they didn't look great.

Among the concerns the FDA cited were problems with how Theranos documents its tests and its failure to get some of its proprietary technology approved.

Now, Theranos has responded, giving some more context to the forms, which were issued after an August 25 visit from the FDA. The forms, called 483s, are issued at the end of inspections when investigators see anything that's not up to FDA standards.

And Theranos, a $10-billion company that says it can do blood tests with a single drop of blood, has come under fire after a Wall Street Journal exposé questioned just how revolutionary the startup was.

Here are the main problems the FDA identified and Theranos' response to each of them.

1. The way Theranos currently documents its tests isn't as clear as it should be.

Theranos' response: Theranos is currently in the process of moving from one set of lab rules (those that follow the Clinical Laboratory Improvement Amendments CLIA) to another (the FDA's), and the lack of clarity is a result of that transitioning process.

2. Theranos' "nanotainers," the proprietary containers the company uses to collect blood, never got regulatory approval, so essentially they're being used illegally.

Theranos' response: Part of their transition to the FDA's rules means that they've stopped using the nanotainers until they're explicitly cleared by the FDA.

Theranos says they've submitted documents to the FDA showing their progress in transitioning from CLIA's set of lab regulations to the FDA's.