We analyzed 276 patients operated on for acute appendicitis between Ja
nuary 1995 and June 1997. In 26 patients intraoperative assessment rev
ealed a pathological finding other than appendicitis. Fifty-nine patie
nts (24 %) had a perforated appendix, 116 acute appendicitis verified
by histological examination, 75 (30 %) chronic fibroplastic appendicit
is or no signs of appendicitis. Patients with histologically acute inf
lammation fulfilled more clinical criteria of appendicitis than those
without (5.1 vs. 3.7). Negative histological findings were most common
in younger females admitted on Mondays and Tuesdays, Clinical observa
tion rather than immediate operation and laparoscopy rather than lapar
otomy appear appropriate for the latter group and may lower the rate o
f negative appendectomies.