The value of 5-hydroxyindolacetic acid levels in spot urine in the diagnosis of acute appendicitis.

BACKGROUND We investigated the value of 5-hydroxyindolacetic acid (5-HIAA) levels in spot urine in the diagnosis of acute appendicitis. METHODS Forty-three patients (11 females, 32 males; mean age 26.3 years; range 16 to 73 years) who were admitted to the emergency room with acute abdominal pain and suspected acute appendicitis were evaluated by means of physical examination, leukocyte counts, urine analysis, measurements of 5-HIAA in spot urine, abdominal x-rays, and sonography. Of these, 25 patients underwent appendectomy after a clinical diagnosis of acute appendicitis. Spot urine analyses were made in all the patients within the first hour of admission with the use of spectrophotometric and colorimetric methods; 5-HIAA levels were read at 540 nm. RESULTS At laparotomy, 22 patients (88%; 3 females, 19 males; mean age 26.18 years; range 15 to 38 years) were found to have acute appendicitis (11 phlegmonous, 11 gangrenous), whereas three patients (12%; 2 females, 1 male) had negative findings. No significant differences were found between patients with confirmed acute appendicitis, patients without appendectomy, and those with negative laparotomy with respect to the mean leukocyte counts and 5-HIAA levels (p>0.05). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 5-HIAA for the diagnosis of acute appendicitis were calculated as 22%, 93%, 71%, 62%, and 63%, respectively. CONCLUSION Measurement of 5-HIAA levels in spot urine is not helpful in the diagnosis of acute appendicitis.