Lactose tolerance test as an alternative to hydrogen breath test in the study of lactose malabsorption

Abstract

ObjectivesLactose malabsorption is generally assessed by hydrogen breath testing (HBT). However, this test is not recommended in patients with high baseline hydrogen concentrations (H2B). In addition, breath testing is not recommended in the current situation created by the COVID-19 pandemic, due to the potential infectiveness of the samples. The objective is to assess concordance between HBT and lactose tolerance test (LTT) depending on H2B concentrations.MethodsA total of 430 patients (40 years, Q1–Q3 = 28–54 years; 66.7% women) suspected of lactose malabsorption were included in the study. Breath and heparinized blood samples were collected at baseline and sequentially after the intake of 50 g of lactose, to measure hydrogen in breath and glycemia in blood, respectively.ResultsH2B was <10 ppm in 69.5% of subjects; 10–20 ppm in 14.7%; and >20 ppm in 15.8% of subjects. In patients with H2B <20 ppm, concordance between HBT and LTT was moderate and consistently improved when the cut-off in LTT was set at 15 mg/dL. The increase in hydrogen and glucose correlated negatively (r=−0.389; p<0.05). The increase in glycemia during LTT was not influenced by H2B levels obtained in HBT.ConclusionsLTT emerges as an alternative to HBT to assess lactose malabsorption in the presence of high H2B levels or when breath testing is not recommended by the circumstances. The best concordance was obtained when the cut-off for LTT was set at 15 mg/dL.

Evaluation of Agreement Between C/T-13910 Polymorphism Genotyping Results and Lactose Tolerance Test Results: A Retrospective Population-Based Study in Brazil

“…In fact, a recent study carried out in Spain with 430 adults found good agreement between hydrogen breath test results and LTT results and concluded that the LTT is a good alternative when the hydrogen breath test cannot be performed (19) . Furthermore, a meta-analysis comparing the C/T-13910 polymorphism genotyping results of Northern Europeans with the hydrogen breath test and LTT results, to determine the ability of these tests to predict the genotype--phenotype relationship, showed that the LTT had higher sensitivity and specificity (94% and 90%, respectively) than the hydrogen breath test (88% and 85%, respectively) (20) .…”

Breath Tests Used in the Context of Bariatric Surgery

“…Sendiny et al (2020) studied lactose malabsorption in patients that had not undergone bariatric treatments. They found that 26.7% of 430 patients had positive results for lactose malabsorption [ 46 ].…”

Modification of baseline status to improve breath tests performance

“…To avoid false negative results, H 2 /CH 4 baseline levels should be low 5 , 6 and interpretation of elevated baseline levels is still uncertain 7 . We have previously shown that baseline high H 2 levels are associated with more positive lactose breath test 8 . For this reason, patient preparation is required 7 , 9 , and it includes avoiding drugs such as antibiotic or laxatives, in the previous days, or procedures that could alter colonic microbiota such as colonoscopy.…”