[Validity of clinical tests to confirm or to exclude the diagnosis of acute appendicitis]

Abstract

Aims: The clinical usefulness of the diagnostic tests (usually employed to diagnose an acute appendicitis in a group of patients in which this diagnosis is clinically highly suspected).

Patients and methods: A cross sectional study was designed. The sample (n = 116) was randomly selected by term and specific days from the patients attending the Emergency Service at Elda General Hospital in a year period. The method used was is a validity study making 2 x 2 tables. We have cross matched the habitual routine tests with: a) the clinical outcome if the patient was not surgically treated, or b) the result of the biopsy for those operated. Being these the gold standard. The validity indexes studied were sensibility (S), specificity (E). The 95% confidence index of the CF were calculated.

Results: Acute appendicitis clinical suspicion was confirmed in 29.4% (IC 95%: 20.8-38). The best validity indexes were: a) kind of pain (S = 81.3; E = 33.8); b) peritoneal inflammatory signs (S = 78.5%, E = 45.9%); c) presence of leucocytosis in blood exam (S = 100%, E = 54.5%), and d) a greater difference in axillary-rectum temperature (S = 13.6%, E = 96.6%). Only leucocytosis reached 0 for PP- and CP-; the blood leucocytosis (PP+ = 47.8%, CP+ = 2.20) and the axillary-rectum temperature (PP+ = 60%, CP+ = 4.0) dissociation were the test with most valuable indexes.

Conclusions: Clinical suspicion of acute appendicitis in a group of patients having a great probability of suffering it over estimates this diagnosis. The symptoms or signs routinely used in the diagnosis did not reach high validity indexes in these patients. They are a poor help to stress or reject the diagnosis of acute appendicitis. To be careful is the main tool the doctors have. Blood leucocytosis is the test that has the best agreement indexes of clinical usefulness and it has the best countence with the gold standard.