There is some question, however, of the effectiveness of CRP once adopted in clinical practice; results of tests performed on those with upper respiratory tract infection were found to have been misinterpreted, and modest effects on prescribing described.22 Some have questioned whether reduced antibiotic prescribing will be seen following implementation in low prescribing settings,23 while others have reported CRP being the main determinant of antibiotic prescription in observational cohorts.24 This evidence concerns the gene CRP and Recurrent upper respiratory tract infections.