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The cut-off criterion for a positive hydrogen breath test in children: a reappraisal
Insights
The 20-ppm criterion for breath hydrogen tests is more accurate for diagnosing lactose maldigestion in preschoolers. This threshold offers better specificity and sensitivity than the 10-ppm criterion.
Area of Science:
- Pediatric Gastroenterology
- Nutritional Science
- Diagnostic Testing
Background:
- Lactose maldigestion is common in preschool children.
- Accurate diagnostic criteria for breath hydrogen tests are crucial for identifying lactose maldigestion.
- Previous studies have used varying cut-off levels for breath hydrogen concentration.
Purpose of the Study:
- To re-evaluate the cut-off criterion for breath hydrogen tests in preschool children.
- To determine the optimal threshold for diagnosing lactose maldigestion.
- To compare the diagnostic accuracy of 10-ppm versus 20-ppm cut-offs.
Main Methods:
- Seventy-three preschool children with adequate nutrition participated.
- Breath hydrogen tests were conducted after consuming intact or prehydrolyzed lactose milk.
- Interval-sampling over 3 hours measured hydrogen concentration.
Main Results:
- Using a 10-ppm cut-off, 83% were classified as incomplete digesters, with 30% false positives on prehydrolyzed milk.
- A 20-ppm cut-off classified 60% as maldigesters, with only 4% false positives on prehydrolyzed milk.
- The 20-ppm criterion showed a better balance of specificity and sensitivity.
Conclusions:
- The 20-ppm cut-off for breath hydrogen tests is superior for diagnosing lactose maldigestion in Guatemalan preschoolers.
- This criterion provides more reliable diagnostic conclusions compared to the 10-ppm threshold.
- Optimizing diagnostic criteria improves the accuracy of identifying lactose maldigestion in pediatric populations.
Abstract:
Seventy-three preschool children with adequate nutritional status underwent interval-sampling, 3-hour breath-hydrogen carbohydrate absorption tests after consuming either 240 ml of intact milk (containing 12 g of lactose) or the same volume of milk with 90-95% of its lactose prehydrolyzed in vitro (containing less than 1 g lactose, with the remaining sugar as glucose and galactose). Results were examined in a reappraisal of the cut-off criterion for the rise of breath H2 concentration signifying biologically incomplete absorption. If the greater than or equal to 10-ppm criterion advocated by some investigators is used, 83% of our subjects would have been classified as incomplete lactose digesters and 30% would have their tests with the monosaccharide-rich milk classified as positive. With the greater than or equal to 20 ppm criterion used in our laboratory and others, the prevalence of lactose maldigestion in the sample becomes 60% and only 4% of subjects have apparent monosaccharide absorption, 96% having a rise below the cut-off level with prehydrolyzed milk. At least in Guatemalan preschoolers, the 20-ppm criterion for a positive breath H2 test provides a superior specificity-sensitivity balance and more reasonable diagnostic conclusions.