Diagnostic characteristics of C reactive protein (CRP) (mg/l) and erythrocyte sedimentation rate (ESR) (mm/h) tests for diagnosing pneumonia in lower respiratory tract infection*

TestsSensitivity (95% CI)Specificity (CI)+LR−LR
*Diagnostic terms defined in glossary. Sensitivity, specificity, and CIs provided by author; LRs calculated from data provided by author.
CRP ⩾1097% (84 to 100)31% (25 to 38)1.40.10
CRP ⩾2091% (75 to 98)51% (44 to 57)1.80.19
CRP ⩾5088% (71 to 97)75% (70 to 81)3.60.17
ESR ⩾1097% (84 to 100)29% (23 to 35)1.40.11
ESR ⩾2078% (60 to 91)57% (51 to 63)1.80.38
ESR ⩾4059% (41 to 76)85% (80 to 90)3.90.48