Hong Kong has long had a deserved reputation for a first-class public health system. It is not founded on criteria like the number of doctors or modern operating theatres or beds per capita, although these are important, or on peer assessment. It is a reputation that has to be upheld every day by performance if it is not to be undermined, and public confidence in the system jeopardised. That said, system failures and medical blunders cannot be eliminated, only kept to a minimum. Transparency and accountability are key to improving patient safety. Two serious examples were disclosed this week which could have had tragic outcomes. There must be full inquiries into both and open outcomes, for the sake of public confidence. In the first, surgeons at Queen Mary Hospital removed a quarter of a patient's lung in the mistaken belief, based on flawed tissue-test results, that he had lung cancer, the Hospital Authority revealed. He actually had tuberculosis. A day later, it was revealed that surgeons at Queen Mary had performed heart and lung transplants on two patients with organs harvested from a donor who was posthumously found to have had cancer in one kidney. A liver transplant on a third patient was aborted. In the first case it is believed the lung sample was contaminated with tissue from another patient, possibly when being collected or processed. In the transplant case all the organs were deemed suitable for donation after examinations laid down by established protocol. The protocol needs to be reviewed. This has also prompted debate on whether Hong Kong should follow the US and the UK in relaxing guidelines on accepting organ donations from some cancer patients. We have always supported appeals for organ donation. But no matter how desperate the need, the Hospital Authority must strive for the most reliable guidelines to ensure organs are suitable for transplant and, if an element of risk is to become acceptable, that patients give informed consent.