A shortage of laboratory staff has forced Llandudno General Hospital to refuse emergency admissions and divert patients up to 20 miles between 4pm and 9am.North West Wales trust director of operations and performance management Martin Jones said recruitment was 'a national problem'.A recent Institute of Biomedical Science survey showed that 88 per cent of NHS laboratories were understaffed. It blamed poor pay - £9,500 for a graduate with five years' training.