How a Lab Error Led to an Unnecessary Surgery

A 32-year-old woman in Switzerland underwent an unnecessary surgery after her lab sample was mixed up at Basel University Hospital. Doctors believed she had cervical cancer. She didn’t — but the procedure went ahead anyway, potentially affecting her ability to carry a pregnancy in the future. In this Mistake of the Week, Mark Graban unpacks how such devastating but preventable errors happen — and why “being careful” isn’t a real safeguard. Drawing on past lab mix-ups he’s written about, Mark explores how system design, workload pressure, and weak error-proofing make these tragedies almost inevitable. This isn’t about bad people or careless workers. It’s about fragile systems — and how hospitals can build processes that catch mistakes before they reach the patient. Because real safety starts with learning, not blaming.