Prospective study on the role of C-reactive protein (CRP) in patients with an acute abdomen.

INTRODUCTION: C-reactive protein (CRP) is used routinely in many hospitals to evaluate patients with an acute abdomen. We assessed CRP levels in non-specific abdominal pain (NSAP) and surgical conditions requiring operative or non-operative intervention. The aim of this study was to identify a level of CRP that can be useful in differentiating these three groups. PATIENTS AND METHODS: All patients older than 25 years and admitted with acute abdominal pain other than those requiring emergency surgery were included. CRP within 24 h was assessed in all patients. Various cut-off values (< 6, > 6-50, > 50-100, > 100-150 and > 150 mg/l) were used to identify a useful diagnostic level of CRP in the 3 groups.
RESULTS: A total of 211 patients were prospectively evaluated - 129 women and 82 men with a mean age of 62.4 years (range, 27-92 years). CRP was performed in 196 within 24 h of admission. Sixty had NSAP while 136 had a surgical condition, of whom 69 had an operation/intervention while the rest were treated non-operatively. The median and interquartile (IQ) range for the three groups were: NSAP, 16 mg/l and 7.75-85.75 mg/l; surgical non-operative group, 75 mg/l and 30.5-150 mg/l; and surgical-operative, 111 mg/l and 42-212 mg/l, respectively. These results were statistically significant (P = 0.001). NSAP was diagnosed in 61% of patients at levels < 6 mg/l compared to 39% of patients in the surgical groups. At levels > 150 mg/l, NSAP was diagnosed in 15% of patients compared to only 54% and 31% for the operative and non-operative groups, respectively.
CONCLUSIONS: Despite statistically significant differences between the three groups, no useful level of CRP could be identified to differentiate between patients with NSAP and those requiring operative or non-operative management.