1. Department of Pediatrics, Denver Health and Hospital Authority, Denver, Colo.
2. Center for Health Systems Research, Denver Health and Hospital Authority, Denver, Colo.
3. Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colo.
4. Department of Pathology, Denver Health and Hospital Authority, Denver, Colo.
5. Department of Pathology, University of Colorado School of Medicine, Aurora, Colo.
6. Department of Emergency Medicine, Denver Health and Hospital Authority, Denver, Colo.
7. Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, Colo.