Positive and negative titres of a new serologic test for the detection of Helicobacter pylori

Abstract

Objective To determine normal ranges for positive and negative titres using a new commercially available serologic enzyme-linked immunosorbent assay for the detection of Helicobacter pylori (MALAKIT, BIOLAB, Limal, Belgium). Methods We studied 463 symptom-free children, aged 2 to 14 years (55% male and 45% female), admitted for elective minor surgery. During routine presurgery blood analysis, 1 ml of venous blood was taken for serology. Results Thirty-four children (7.3%) had a positive litre. Although we were able to observe an increase in the number of seropositive subjects with age, there was no significant increase in titre with age for both positive and negative titres. In 25 seropositive patients, a control serology and ¹³C-urea breath test were performed 6 to 9 months later. In all but one patient (96%), both control examinations were positive. ¹³C-urea breath tests were also performed in 65 randomly selected seronegative children and were all negative. Conclusions A positive ¹³C-urea breath test suggests that the seropositive children were infected with H. pylori. Since ¹³C-urea breath tests were positive in seropositive and negative in seronegative children, we validated the manufacturer's previously established cut-off values, based on 119 paediatric patients, in a significantly larger patient population. The proposed cut-off limit for children for the MALAKIT test is 0.21 optical density units at 405 nm. The significance of these ‘healthy H. pylori carriers' remains to be elucidated.