Diagnostic value of an initial C-reactive protein level in acute surgical patients

In surgical patients, C-reactive protein (CRP) levels are often measured as a marker of inflammation and infection. However, the diagnostic and prognostic value of a single initial CRP measurement in the acute presentation has not been well established. This study was performed to investigate the usefulness of measuring CRP in such a setting.

CRP levels were measured retrospectively in 473 surgical patients who presented to the Royal Adelaide Hospital emergency department. This was correlated with patient outcomes, defined by the need for imaging tests and/or surgical interventions, the length of hospital stay and 30-day mortality. Spearman's rank correlation and one-way analysis of variance were used for statistical analysis.

Of 473 patients, 42% had a CRP test in the emergency department within 24 h of admission. Approximately 80% of patients required imaging for diagnosis and 40% required surgery, regardless of the initial CRP level. No correlation was evident between initial CRP level and length of hospital stay (r= 0.06). One-way analysis of variance revealed no variation in levels between patients who required imaging or had surgery compared to those who did not, with P-values of 0.76 and 0.85, respectively. Two patients died within 30 days of presentation.

CRP has poor diagnostic and prognostic capabilities as a single initial measurement in acute surgical patients. The statistical analyses imply that CRP levels are unable to accurately predict outcomes of such patients. Therefore, we suggest that CRP should not be used as a routine screening tool.