Early peak of hydrogen during lactose breath test predicts intestinal motility

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 (H 2 ) ≥ 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 H 2 > 20 ppm, a positive GHBT for a peak >12 ppm and we considered a normal OCCT a peak of H 2 ≥ 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 (<90 min) of H 2 (≥20 ppm) were enrolled as case, and 47 pts matched for sex and age with a peak of H 2 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 < 0.05). The presence of an early peak of H 2 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.

Role of Small Intestinal Bacterial Overgrowth (SIBO) and Inflammation in Obese Children

“…To reduce this risk, LBT was used in this study, although this test is not without criticism. Conventional double-peak criteria on LHBT lack sensitivity (31-68%) and the recently proposed early-peak criterion, the one used in this study, can lead to false positive results with specificity of 65-97.9% (17,18). Thirdly, the study did not include a control group of non-overweight/obese children with SIBO in whom inflammatory markers have been studied.…”

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy

“…Though GHBT is highly specific (78% to 97%),41,42 it is quite insensitive (15.7% to 62%) 42,43. In contrast, conventional double-peak criteria on LHBT lack sensitivity (31% to 68%) and the recently proposed early-peak criterion (rise in breath hydrogen within 90 minutes by 20 ppm above basal following lactulose ingestion) often gives false positive result with specificity of 65% to 97.9% 39,44. This is the reason for overestimation of frequency SIBO (as high as 78%) in the initial studies from United States 40.…”

“… 42 , 43 In contrast, conventional double-peak criteria on LHBT lack sensitivity (31% to 68%) and the recently proposed early-peak criterion (rise in breath hydrogen within 90 minutes by 20 ppm above basal following lactulose ingestion) often gives false positive result with specificity of 65% to 97.9%. 39 , 44 This is the reason for overestimation of frequency SIBO (as high as 78%) in the initial studies from United States. 40 In fact, the early-peak criterion on LHBT, which was used in the initial studies on SIBO in patients with IBS, presumed that normal mouth to cecum transit time is more than 90 minutes in spite of the observation that it may be shorter.…”

Prevalence of lactose intolerance among natives and expats in Kuwait

“…One of the non-invasive tests is lactose tolerance test that measures the glucose levels which result from degradation of lactose in several blood samples monitored at 0, 60 minutes and then 120 minutes after lactose intake, a less than 20 mg/dL (1.1 mmol/L) increase in blood glucose level with the presence of symptoms is considered diagnostic ( 9). On the other hand, lactose breath test (LBT) is another non-invasive test that measure the hydrogen in the expired air, in three hours' duration with at least 30 minutes samples interval, The test is considered positive if the hydrogen value in the expired air increases of 20 parts per million (ppm) above the baseline (10). Lactase activity assay in small bowel biopsy is considered the gold standard for diagnosing lactose malabsorption (11), however is not commonly used as it is invasive and needs small bowel sampling by endoscopy.…”