Holmes Testifies About ‘Big Idea’ That Led to Theranos

SAN JOSE, Calif.—Elizabeth Holmes took jurors into the Theranos Inc. lab Monday during testimony at her criminal-fraud trial, describing ways the startup sought to reduce errors in lab testing and miniaturize traditionally bulky blood-testing machines.

“We thought this was a really big idea,” Ms. Holmes said of Theranos’s attempts to remove human error from steps involved in the testing process by automating it.