Evaluation of a rapid whole blood test to detect Helicobacter pylori infection in children.

BACKGROUND: Rapid, patient near tests for detecting antibodies against Helicobacter pylori are offered for clinical use. We evaluated the BM-Test (Boehringer Mannheim, Germany; identical to the Helisal Rapid Blood Test) in children with recurrent abdominal pain. METHODS: The BM-Test and 13C-urea breath test (UBT) were performed in 195 children (4-18 years). Symptoms were assessed using a 4-week diary. Upper endoscopy was performed in all UBT-positive children and in UBT-negative children with symptoms suggestive of organic disease. H. pylori status was considered positive if at least two of three methods (UBT, histology or rapid urease test) or culture were positive. RESULTS: After exclusion of children with previous H. pylori therapy (n = 8) and undetermined H. pylori status (n = 1), 61/186 (33%) children were H. pylori positive. The BM-Test in relation to H. pylori status revealed a sensitivity of 54%, specificity of 90%, a likelihood ratio of 5.2 for a positive, and of 0.4 for a negative test result. Accuracy of the test was independent of ethnicity, gender, age, family history for ulcer disease, frequency or severity of abdominal symptoms, epigastric tenderness, type of blood sampling (capillary versus venous) and DOB values of the UBT. In eight previously treated children, the test gave one false-positive and three false-negative results. CONCLUSIONS: Almost half of H. pylori-infected children and 10% of non-infected children were misclassified by the BM-Test. False-negative results are not related to young age or certain ethnic groups. The poor performance makes the test unsuitable for epidemiological and clinical use in children.

Rectal biopsy for diagnosis of intestinal neuronal dysplasia in children: a prospective multicentre study on interobserver variation and clinical outcome.

BACKGROUND: Intestinal neuronal dysplasia (IND) of the colonic submucous plexus is considered to be a congenital malformation of the enteric nervous system causing symptoms resembling those of Hirschsprung's disease. In contrast with the established diagnosis of aganglionosis using enzyme histochemistry, controversy exists over the diagnostic criteria of IND on rectal biopsies previously defined by a consensus report and the causal relation between morphological findings and clinical symptoms. AIMS: The interobserver variability was prospectively investigated with respect to final diagnoses and several histological features in rectal biopsy specimens from children suspected of having colonic motility disturbances. METHODS: 377 biopsy specimens from 108 children aged 4 days to 15 years were independently coded without knowledge of clinical symptoms by three experienced pathologists for 20 histological features, and a final diagnosis was given for every case. Interobserver variation for the different items and the final diagnosis were analysed using Cohen's kappa statistic. Clinical data at biopsy and outcome after 12 months were related to morphological findings. RESULTS: The three pathologists agreed completely with respect to the diagnosis Hirschsprung's disease (kappa = 1), but in only 14% of the children without aganglionosis. In 15 (17%) of the 87 children without aganglionosis, at least one pathologist judged the case as normal, while another diagnosed IND. kappa values were close to the zero value expected by chance for the diagnoses normal and IND. Young age was related to the presence of several morphological features-for example, acetylcholine esterase staining and presence of giant ganglia. Children with chronic constipation diagnosed as having IND, given no other specific diagnosis by any of the pathologists, were significantly younger (median 8.8 months) and had a higher cure rate after one year (60%) than constipated patients considered by all observers to have no histological abnormalities (median 6.1 years, cure rate 23%). CONCLUSIONS: In contrast with Hirschsprung's disease, there is a high interobserver variation with regard to the different morphological features and final diagnosis of IND, based on the criteria and conditions of the previous consensus report. The high frequency of histological "abnormalities" in young infants suggests that some of the features may represent a normal variant of postnatal development rather than a pathological process. Investigations using more refined and morphometric methods in rectal specimens from infants and children without bowel disease are needed to define the normal range of morphological appearance at different ages. These preliminary data indicate that, with current knowledge, rectal biopsy for diagnostic purposes should only be performed in constipated children for diagnosis of Hirschsprung's disease.