NHS patients have the right to receive elective pre-planned consultant-led care within 18 weeks of being referred for treatment. In 2012-13, there were 19.1 million referrals to hospitals in England, with hospital-related costs of around £16 billion. The standards are that 90% of patients admitted to hospital, and 95% of other patients, should have started treatment within 18 weeks of being referred. In April 2013, NHS England introduced zero tolerance of any patient waiting more than 52 weeks. The Department of Health cannot be sure that the waiting time data NHS England publishes, based on information from NHS trust, is accurate. Trusts are struggling with a hotchpotch of IT and paper based systems that are not easily pulled together, which makes it difficult for them to track and collate the patient information needed to manage and record patients' waiting time. The National Audit Office (NAO) found that waiting times for nearly a third of cases it reviewed at seven trusts were not supported by documented evidence, and that a further 26% were simply wrong. Multiple organisations have a quality assurance role. However the external audit provided in the past by the Audit Commission has yet to be replaced and the Department acknowledged the need to do so, with regular spot checks being undertaken to ensure accuracy. But responsibilities have not been clearly defined.