1. Royal Bolton Hospital, Farnworth, Bolton BL4 0JR, UK.
2. The Royal Oldham Hospital, Rochdale Road, Oldham OL1 2JH, UK.
3. Laboratory Medicine Academic Group, Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
4. Hope Hospital, Stott Lane, Salford M6 8HD, UK.