The Food and Drug Administration declared the tiny vials used by Theranos Inc. to collect finger-pricked blood from patients an “uncleared medical device” that the laboratory company was shipping across state lines.

Inspection reports posted on the agency’s website Tuesday also showed that the FDA found deficiencies in Theranos’s processes for handling customer complaints, monitoring quality and vetting suppliers.

In a statement Tuesday, Theranos’s general counsel, Heather King, said company officials “addressed and corrected” all the observations made by FDA inspectors “at the time of, or within a week of, the inspection and have submitted documents to FDA that say so, including extensive documentation.”

Government officials also warned the Palo Alto, Calif., company that it would receive a formal warning letter if it didn’t take action on the vials, called nanotainers, according to a person familiar with the matter.

Theranos said on Wednesday in a statement on its website that “no warning letter was or has been discussed or mentioned.”