1. Istituto Superiore di Sanità
2. 00161 Rome
3. Italy
4. Department of Clinical Biochemistry
5. Black Country Pathology Services
6. Sandwell General Hospital
7. West Bromwich
8. UK
9. Reading Scientific Services Ltd
10. LGC
11. Department of Biochemistry
12. Manchester University NHS Foundation Trust
13. Manchester M13 9WL
14. Department of Chemistry
15. University of Massachusetts Amherst
16. Amherst
17. USA