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Lactose Breath Hydrogen Test

See Also
1. Lactose Intolerance
2. Lactose Tolerance Test
Indications
1. Lactose Intolerance testing
Efficacy
1. Preferred over Lactose Tolerance Test
2. Test Sensitivity: 90%
Technique
1. Measure baseline breath hydrogen concentration
2. Patient ingests lactose
  1. Classic: 25 to 50 grams lactose
  2. Physiologic: 12 grams lactose (same as in 8 oz milk)
3. Measure breath hydrogen concentration in 3 to 8 hours
  1. Increase >20 ppm suggests Lactose Intolerance
False negative causes
1. Gastrointestinal flora absent (e.g. recent antibiotics)
False positive causes
1. Recent Exercise
2. Aspirin use
3. Tobacco smoking
References
1. Powell in Goldman (2000) Cecil Medicine, p. 711

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