[1] Univ Calgary, Alberta Childrens Hosp, Res Inst, Cumming Sch Med,Sect Pediat Emergency Med & Gastr, Calgary, AB, Canada
[2] Univ Toronto, Hosp Sick Children, Dept Pediat, Div Pediat Emergency Med & Clin Pharmacol & Toxic, Toronto, ON, Canada
[3] Alberta Precis Labs, Publ Hlth Lab, Edmonton, AB, Canada
[4] Univ Alberta, Dept Lab Med & Pathol, Edmonton, AB, Canada
[5] Washington Univ, Dept Pediat, Sch Med, Div Gastroenterol Hepatol & Nutr, St Louis, MO 63130 USA
[6] Univ Utah, Dept Pediat, Salt Lake City, UT USA
[7] Univ Alberta, Women & Childrens Hlth Res Inst, Dept Pediat, Edmonton, AB, Canada
[8] Univ New Mexico, Dept Emergency Med, Hlth Sci Ctr, Albuquerque, NM 87131 USA
[9] George Washington Univ, Childrens Natl Hosp, Dept Pediat & Emergency Med, Div Emergency Med,Sch Med & Hlth Sci, Washington, DC USA
[10] Rhode Isl Hosp Hasbro Childrens Hosp, Dept Emergency Med, Providence, RI USA
[11] Brown Univ, Providence, RI 02912 USA
[12] Schulich Sch Med & Dent, Dept Pediat, London, ON, Canada
[13] Schulich Sch Med & Dent, Dept Internal Med, London, ON, Canada
[14] Schulich Sch Med & Dent, Dept Epidemiol, London, ON, Canada
[15] Schulich Sch Med & Dent, Dept Biostat, London, ON, Canada
[16] Columbia Univ, Dept Emergency Med, Med Ctr, New York, NY USA
[17] Univ Toronto, Hosp Sick Children, Dept Pediat, Div Pediat Emergency Med, Toronto, ON, Canada
[18] Univ Michigan, Dept Emergency Med & Pediat Michigan Med, Ann Arbor, MI 48109 USA
[19] Univ Cincinnati, Coll Med, Div Emergency Med, Cincinnati Childrens Hosp Med Ctr, Cincinnati, OH 45229 USA
[20] Univ Cincinnati, Coll Med, Dept Pediat, Cincinnati, OH USA
[21] Univ Montreal, Dept Pediat Emergency Med & Pediat, Montreal, PQ, Canada
[22] Univ Michigan, Dept Emergency Med & Pediat, Ann Arbor, MI 48109 USA
[23] Univ Calif Davis, Dept Emergency Med & Pediat, Sch Med, Sacramento, CA USA
[24] Dalhousie Univ, Dept Emergency Med, IWK Hlth, Halifax, NS, Canada
[25] Northwestern Univ Feinberg, Ann & Robert H Lurie Childrens Hosp Chicago, Dept Pediat, Div Emergency Med,Sch Med, Chicago, IL USA
[26] Univ Ottawa, Dept Pediat & Emergency Med, Ottawa, ON, Canada