TITLE:
Early peak of hydrogen during lactose breath test predicts intestinal motility
AUTHORS:
Veronica Ojetti, Teresa Antonella Di Rienzo, Giovanna D’Angelo, Emidio Scarpellini, Gianluca Rizzo, Maria Chiara Campanale, Antonio Gasbarrini
KEYWORDS:
Lactose Breath Test; Transit Time; IBS; Hydrogen
JOURNAL NAME:
Open Journal of Gastroenterology,
Vol.4 No.1,
January
23,
2014
ABSTRACT: Lactose breath test (LBT) is considered the gold
standard for the diagnosis of lactose malabsorption. The test is considered
positive for a peak of hydrogen (H2) ≥ 20 parts per million (ppm)
above the baseline. Some patients (pts) showed a rapid peak between 30 and 90
minutes after lactose ingestion. The aim of this study was to evaluate the
predictive value of an early peak during a LBT and an accelerated oro-cecal
transit time (OCTT). We
retrospectively analyzed all pts who referred to our Gastroenterology unit for
Irritable Bowel Syndrome, from January to September 2012, who performed LBT,
glucose and lactulose breath test. We consider a positive LBT for a peak of H2 > 20 ppm, a positive GHBT
for a peak >12 ppm and we considered a normal OCCT a peak of H2 ≥ 10 ppm between 75 ± 105 min
after lactulose load. The correlation between LBT and OCTT was evaluated by
Pearson score. 93 pts (65 F/28 M mean age 47 ± 6 years) with a positive LBT,
without small intestinal bacterial overgrowth were analyzed: 46 pts (32 F/14 M;
mean age 48 ± 6 years) with an early peak (2 (≥20 ppm) were enrolled as
case, and 47 pts matched for sex and age with a peak of H2 after 90 min were enrolled as
controls. 72% (33/46) of the group with an early peak showed an accelerated,
17% (8/46) a normal and 11% (5/46) a delayed OCTT. Meanwhile, in control group
40.4% (19/47) showed a normal, 57.5% (27/47) a delayed and just 1 pts an accelerated
OCTT. The specificity and sensibility of LBT
for an accelerated OCTT were 97.9% and 71.7% respectively. The positive
predictive value of LBT for an accelerated OCTT is 97.1%; the negative predictive
value is 78%. There is a significant correlation between LBT and OCTT (p The presence of an early peak of H2 between 30 and 90 min after the ingestion of 25 gr of lactose could
predict the presence of an accelerated OCTT in 97% of pts. If confirmed by
further study, in this subset of pts, lactulose breath test for evaluating OCTT
could be avoided.