1. Department of Clinical Pharmacy, Diakonessenhuis, P.O. Box 80250, 3508 TG Utrecht, The Netherlands.
2. Department of Internal Medicine, Bosch Medicentrum, 's-Hertogenbosch, The Netherlands.
3. Department of Internal Medicine, Diakonessenhuis.
4. Central Hospital Pharmacy, Bosch Medicentrum.
5. Laboratory for Public Health, Diakonessenhuis.