The accuracy of C-reactive protein in the diagnosis of acute appendicitis compared with that of clinical diagnosis.

BACKGROUND: Acute appendicitis is one of the most common surgical emergencies. Its diagnosis is usually made depending on presenting history, clinical evaluation and laboratory tests. It has been estimated that the accuracy of the clinical diagnosis of acute appendicitis is lying between 76% and 92% (1). Negative appendectomies are one of the burdens facing not only the general surgeon but also the patient himself and the society as a whole, since appendectomy, as any other operation, results in socio-economic impacts in form of lost working days and declined productivity.

OBJECTIVES: To determine the accuracy of c-reactive protein (CRP) in the diagnosis of acute appendicitis in comparison with the accuracy of clinical diagnosis.

METHODS: This is a prospective study of all appendectomized patients during a one-year period in King Hussein Hospital in Amman/Jordan.

RESULTS: A total of 98 patients were included in this study. The diagnosis of acute appendicitis was histopathologically confirmed in 89 patients (91%), while 9 normal appendixes (9%) were removed. The readings of CRP were ranging between 0 and 11.7 mg/l (mean 5.6 mg/l) in patients with normal appendixes, and between 6-93.4 mg/l (mean 36.2 mg/l) in patients with acute appendicitis. Normal CRP readings were found in 4 patients with acute appendicitis, and of the 9 cases with normal appendectomy, CRP level was elevated in only one patient, so the CRP levels were true (positively or negatively) in 93 patients and it was false positive in one patient (11%) and false negative in 4 patients (4%). On the other hand, the clinical diagnosis was correct in 89 cases (91%) and false in 9 cases (9%), the difference is statistically significant (p value = 0.009).

CONCLUSIONS: We conclude that CRP is very helpful in the diagnosis of acute appendicitis, but it doesn't replace the clinical skills of general surgeons.