The demand for tests related to melamine-linked kidney stones has dropped enough that the Hospital Authority has decided to close one of its special assessment centres, it announced yesterday. This reduces to eight the number of assessment centres in the hospital clusters. 'As the service demand at the [centres] has levelled off and become quite steady, recently, the Hospital Authority has decided to cease the service at North District Hospital,' an authority spokesman said yesterday. On September 23, the authority opened 18 designated clinics to provide free assessments to children under 12 who had consumed milk products connected to the melamine scare and had relevant symptoms. When necessary, patients were referred to special assessment centres in the seven hospital clusters for further assessment and treatment. Ten children have been diagnosed with kidney stones. Nine of them passed the stones after conventional treatment, while one underwent surgery in a private hospital, said director for quality and safety Leung Pak-yin. Authority chief executive Shane Solomon said the service would continue until the end of March, and that the authority had completed retesting the 10 children. 'So far, the retests have shown that the stones have passed out already, with just drinking water,' he said. The authority would conduct research on the short- and long-term effects of melamine toxicity, he said. All patients tested in the special assessment centres would be followed up for possible long-term complications. 'We are in the process of designing, with the Food and Health Bureau, to see what sort of follow ups we will be doing in the coming months,' Mr Solomon said. The authority's clinics have been sought out by 46,245 people and conducted 16,303 assessments. No new kidney cases related to melamine-tainted milk were reported yesterday.