Lactose Intolerance

Lactose intolerance is a common digestive problem where the body is unable to digest lactose, a type of sugar found mainly in milk and dairy products. Testing for lactose intolerance can help individuals determine whether their symptoms are related to lactose or possibly another condition.

Here are some common tests used to diagnose lactose intolerance:

  1. Hydrogen Breath Test:
    1. The most common test for lactose intolerance.
    2. After fasting, the patient consumes a lactose-containing beverage.
    3. If the lactose is not properly digested, it will ferment in the colon, producing hydrogen which is then absorbed into the bloodstream and exhaled in the breath.
    4. The breath is then analyzed at regular intervals to measure the amount of hydrogen. Elevated levels suggest improper lactose digestion, which is indicative of lactose intolerance.
  2. Lactose Blood Sugar Test:
    1. After fasting, the patient drinks a liquid containing lactose.
    2. Blood samples are taken over a two-hour period to measure blood sugar (glucose) levels.
    3. If lactose is properly digested, blood glucose levels will rise. If there’s no change or only a small change in blood glucose, this may suggest lactose intolerance.
  3. Stool Acidity Test:
    1. Used primarily for infants and young children.
    2. After consuming lactose, undigested lactose ferments in the colon, producing lactic acid and other fatty acids, which can be detected in a stool sample.
  4. Dietary Elimination and Challenge:
    1. Not a clinical test, but often used as an initial assessment.
    2. The person removes all lactose-containing foods and beverages from their diet for several weeks and notes if symptoms improve.
    3. After the elimination period, lactose is reintroduced, and the person monitors for symptom recurrence.
  5. Genetic Testing:
    1. Some populations have higher frequencies of lactose intolerance due to genetic factors.
    2. A genetic test can identify specific gene variants associated with decreased lactase production, but it’s less commonly used than other diagnostic methods.