CLINICAL-ASSESSMENT OF THE BACTERIAL LOAD OF HELICOBACTER-PYLORI ON GASTRIC-MUCOSA BY A NEW MULTI-SCALED RAPID UREASE TEST

The present study tests the efficacy of the multi-scaled urease test ( MUT) in detecting Helicobacter pylori infection and determines whether the MUT can predict the bacterial density on histology. A total of 11 1 sets of gastric specimens were obtained from patients with dyspepsia but without recent bleeding. Two biopsies were taken as closely as po ssible in each set. One sample was used for the MUT (Hp fast; GI Suppl y, Camp Hill, PA, USA), while the other was used to determine the hist ological density of H. pylori by modified Giemsa stain (grade 0-5). Th e results of MUT were interpreted as negative if the colour was yellow or bright green (reaction score 0) and positive if the colour was gre en, light blue, or blue (reaction score 1, 2 and 3, respectively). The reaction scores of MUT were recorded sequentially at 15 and 30 min an d 1, 4 and 24 h. On the basis of histological confirmation, MUT had a sensitivity of 89.6%, a specificity of 88.2%, a positive predictive va lue of 94.5% and a negative predictive value of 78.9%. Focusing on spe cimens with the presence of bacteria under histology, 77 specimens wer e divided into five subgroups by grades of density of H. pylori (HPD1- 5). The reaction scores had become sequentially elevated from 30 min t hrough to 24 h in each subgroup. For subgroups HPD4 and 5, the positiv e rates of MUT were 70.6 and 66.6%, respectively, as early as 30 min a nd progressed to 100% within 4 h. In contrast, the positive rate for t he HPD1 subgroup was 16.6% at 4 h and increased to only 62.5% at 24 h. In subgroups HPD 2 and 3, the positive rates were less than 30% at 30 min, but became more than 66.6% at 4 h and were 100% at 24 h. The ear ly (i.e. mean value of reaction scores before 4 h) and late (24 h) mea n reaction scores disclosed two elevated trends as the density of H. p ylori increased (early: 0.2, 0.7, 0.8, 1.5, 1.2; late: 1.4, 2.3, 2.6, 3.0, 3.0; P< 0.05). In conclusion, MUT is a reliable method for the di agnosis of H. pylori infection. It can also indirectly predict the den sity of H. pylori on histology.