A survey of caffeine measurements in routine samples submitted for theophylline assay.
D002110:Caffeine / Q000097:blood*; D002845:Chromatography; D006801:Humans; D007158:Immunologic Techniques; D007231:Infant, Newborn; D007234:Infant, Premature; D008875:Middle Aged; D013806:Theophylline / Q000097:blood*
D002110:Caffeine; D013806:Theophylline