Utility of stool sample-based tests for the diagnosis of Helicobacter pylori infection in children

Epidemiology and diagnosis of Helicobacter pylori infection

Medline, PubMed and the Cochrane databases were searched on epidemiology and diagnosis of Helicobacter pylori for the period of April 2011-March 2012. Several studies have shown that the prevalence of H. pylori infection is decreasing in adults and children in many countries. Various diagnostic tests are available, and most of them have high sensitivity and specificity. The Maastricht IV/Florence consensus report states that the urea breath test using (13)C urea remains the best test to diagnose H. pylori infection. Among the stool antigen tests, the ELISA monoclonal antibody test is recommended. All these tests were used, either as a single diagnostic test or in combination, to investigate H. pylori infection among different populations throughout the world. Of particular interest, current improvements in high-resolution endoscopic technologies enable increased diagnostic accuracy for the detection of H. pylori infection, but none of these techniques, at present, are specific enough for obtaining a real-time diagnosis of H. pylori infection.

Targeted provision of oral iron: the evolution of a practical screening option

Universal oral iron supplementation, undertaken according to 1998 WHO guidelines, produced adverse consequences among some children in malaria-endemic areas. Prompted by the Pemba trial, which revealed excessive hospitalizations and deaths, WHO advised that iron supplementation in such regions be accompanied by previous screening for iron deficiency. This agenda, however, poses issues of cost, benefit, acceptability, technical feasibility, and reliability of such screening. The cost of equipment and personnel is balanced against savings from iron supplements spared and treatment for morbidity averted. Costs aside, the most efficacious acceptable screening approach for avoiding hospitalization and deaths must be fielded. Screening before supplementation can be used to assess hematological, iron, and possible inflammatory status to differentiate the source of decreased hemoglobin concentration. Iron deficiency has often been inferred from hematological status markers. The need for extraction of blood, albeit capillary in origin, and high assay costs limit the use of validated methods in screening. Noninvasive methods, i.e., not requiring the extraction of blood, provide the most acceptable and potentially least expensive approach for determining hematological or iron status. Although a noninvasive technique for iron and inflammatory status would be the ideal, it is unattained. Field-friendly, skin-probe hemoglobin devices, derived from instruments for clinical settings, are being developed and tested for eventual rollout in malarial areas. Given a firm grounding for the theoretical requirements needed to advance the screening agenda, evaluation and monitoring of the performance of screening devices can proceed hand in hand.

13C-urea breath test for the diagnosis of Helicobacter pylori infection in children: a systematic review and meta-analysis

BACKGROUND

The (13) C-urea breath test ((13) C-UBT) is a safe, noninvasive and reliable method for diagnosing H. pylori infection in adults. However, the test has shown variable accuracy in the pediatric population, especially in young children. We aimed to carry out a systematic review and meta-analysis to evaluate the performance of the (13) C-UBT diagnostic test for H. pylori infection in children.

METHODS

We conducted a systematic review of the PubMed, Embase and Liliacs databases including studies from January 1998 to May 2009. Selection criteria included studies with at least 30 children and reporting the comparison of (13) C-UBT against a gold standard for H. pylori diagnosis. Thirty-one articles and 135 studies were included for analysis. Children were stratified in subgroups of <6 and ≥6 years of age, and we considered variables such as type of meal, cutoff value, tracer dose, and delta time for the analysis.

DISCUSSION

The (13) C-UBT performance meta-analyses showed 1, good accuracy in all ages combined (sensitivity 95.9%, specificity 95.7%, LR+ 17.4, LR- 0.06, diagnostic odds ratio (DOR) 424.9), 2, high accuracy in children >6 years (sensitivity 96.6%, specificity 97.7%, LR+ 42.6, LR- 0.04, DOR 1042.7), 3, greater variability in accuracy estimates and on average a few percentage points lower, particularly specificity, in children ≤6 years (sensitivity 95%, specificity 93.5%, LR+ 11.7, LR- 0.12, DOR 224.8). Therefore, the meta-analysis shows that the (13) C-UBT test is less accurate for the diagnosis of H. pylori infection in young children, but adjusting cutoff value, pretest meal, and urea dose, this accuracy can be improved.