A Whistle-Blower Jolts Sleepy Elizabeth Holmes Trial to Life (1)

A former Theranos Inc. lab worker-turned-whistle-blower jolted Elizabeth Holmes’s trial, animating allegations that the blood-testing startup was a fraud with her descriptions of wrongdoing to patients and hinting at more to come Wednesday.

Wearing a pinstriped jacket, Erika Cheung strode past the defendant to the witness stand and confidently told jurors how she was initially “star-struck” when Holmes interviewed and hired her in 2013 as a lab associate at Theranos.

The three-month trial had gotten off to a somnambulant start with the first witness giving hours of dry testimony about accounting and stock-option irregularities. When Cheung spoke, jurors sat ...