Evaluation of a commercial latex test for serological diagnosis of Helicobacter pylori infection in treated and untreated patients.

The value of a commercially available latex test (Pyloriset) for the diagnosis of Helicobacter pylori infection by demonstration of specific antibodies was compared with that of direct diagnostic methods such as culture, biopsy-urease test and microscopy of fuchsin-stained smears. The sera were from 136 patients who prior to this study either had or had not been treated for Helicobacter pylori-infection simultaneously with amoxicillin (3 x 750 mg/day) and metronidazole (3 x 500 mg/day) for 12 days. On average, the sensitivity of the test was 90%. The specificity with sera from untreated patients was 75.9%; with sera from treated patients specificity was 22.2%, 28% and 20% 1, 3 and 6 months respectively after start of treatment. Only as late as one year after the onset of chemotherapy did the specificity return to 67%. Because of its low specificity this test does not offer any advantage over other tests in the detection of Helicobacter pylori-infection or in monitoring the chemotherapeutic success.