The chief executive of the Hospital Authority has apologised to a woman who suffered a brain haemorrhage after receiving the wrong type of blood in a transfusion. A day after the incident at the Caritas Medical Centre in Sham Shui Po came to light, Dr Leung Pak-yin admitted there had been a serious mistake. 'We are deeply sorry to the victim and her family,' Leung said. The 64-year-old woman developed a brain haemorrhage after being given blood type A, instead of type B. She was being treated at Kwong Wah Hospital in Yau Ma Tei, where she was said to be in a serious condition last night. Initial investigations found that laboratory staff at Caritas had swapped the woman's blood test results with those of another patient. The other patient did not require a transfusion and had already been discharged from hospital. A panel of medical experts will investigate the incident and is expected to issue a report within eight weeks. The woman was admitted to the Caritas centre on August 9 suffering from scoliosis - a curved spine, with a narrowing of the spinal column, a condition known as spinal stenosis Dr Derrick Au Kit-sing, the authority's head of human resources, said yesterday that the blunder was a one-off. 'As far as we know, the mistake this time occurred in the laboratory but not during the blood sampling, blood grouping and blood transfusion, so there was not a fault in the bar-code system,' he said. Since 2008, public hospitals have used a bar-code system for labelling blood samples in an effort to prevent specimen mix-ups at hospitals. Under the system, staff who want to print a label for a blood sample must first scan a bar code on a patient's wristband, then another bar code on a document containing the patient's particulars. Only if both barcodes match will the label be printed. Noting that such incidents were extremely rare, a spokeswoman for the authority said that the only previous case on record occurred in September 2004.