II. Indications

III. Efficacy

IV. 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

V. False Negative causes

  1. Gastrointestinal flora absent (e.g. recent antibiotics)

VI. False Positive causes

VII. References

  1. Powell in Goldman (2000) Cecil Medicine, p. 711

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