SEMIQUANTITATIVE EVALUATION FOR DIAGNOSIS OF HELICOBACTER-PYLORI INFECTION IN RELATION TO HISTOLOGICAL-CHANGES

Objectives: Several methods are used to detect Helicobacter pylori (HP ) infection. However, few reports have evaluated the accuracy of each method and compared the grade of HP infection with the severity of his tological changes. HP infection was evaluated semiquantitatively in re lation to the severity of gastritis, and the sensitivity, specificity, and accuracy of several methods to detect HP infection were compared. Methods: Biopsy specimens, obtained from a total of 64 patients who u nderwent endoscopy for evaluation of gastroduodenal diseases, were stu died using a rapid urease test, culture, and histological assessment. An immunohistochemical method was used as the gold standard and graded according to the number of individual bacteria seen, as follows: 0 = 0; 1+ = <10; 2+ = 10-29; 3+ = 30-99; 4+ = >100. The severity of gastri tis was evaluated histologically in each specimen and compared with th e grade of HP infection. Results: The rapid urease test had a sensitiv ity of 53%, specificity of 100%, and accuracy of 73%. The culture meth od had a sensitivity of 75%, specificity of 100%, and accuracy of 86%. Sensitivities of the rapid urease test and the culture method decreas ed in a positive correlation with the decrease in total number of HP b acteria counted. Using rapid urease test, sensitivity was <30% when th e grade of HP infection was less than or equal to 2+, whereas 100% sen sitivity was obtained when the grade of HP infection was 4+. On the ot her hand, sensitivity of the culture method remained between 80% and 9 0% when HP infection was greater than or equal to 2+. The severity of gastritis determined with Rauws scores increased in a positive correla tion with the grade of HP infection as evaluated by immunohistochemica l stain. Conclusions: The rapid urease test and culture of HP may resu lt in false-negative tests for a mild infection, although they had hig h sensitivity and specificity for moderate to sever infection. Immunoh istochemical stain provides a reliable semiquantitative diagnosis of H P infection and a positive corelation with histoligcal changes. Clinic ians should be aware of the characteristics of each method to detect H P infection and select the appropriate one(s) for their purposes. (C) 1998 by Am. Coll. of Gastroenterology.