Lactose Malabsorption Test
 
 

The Lactose Malabsorption Breath Test is used to help diagnose conditions in which the patient is unable to digest the sugar that is in milk. The following explanation will help you understand the importance of following the instructions closely.

People who have lost the ability to digest milk sugar (lactose) have a condition called lactose malabsorption. The sugar molecule remains in the intestine and is carried to the colon (large intestine). Bacteria there digest the lactose and release hydrogen (H2) and methane (CH4). Some of the H2 and CH4 is reabsorbed into the blood stream, carried to the lungs, and exhaled. Hydrogen and methane are normally not produced in the body except by bacterial action on intestinal contents. Samples of air from the lungs are analyzed at specific times after ingesting a standard dosed by the physician during the examination, to confirm or reject a diagnosis of lactose malabsorption.

 

Patient Preparation for the Test
  1. The patient SHOULD NOT eat high fiber or slowly digesting foods the day before the test because they may still be present in the colon the next day. Such foods include bran, coarse breads, nuts, beans and similar vegetables. Avoidance of such foods will reduce the chance of hydrogen and methane production from other food sources during the period of the test.
  2. The patient SHOULD fast overnight (at least 12 hours) before the test, consuming no food and having only water to drink. This will further eliminate the chance of other foods interfering with the test.
  3. The patient SHOULD NOT sleep or exercise vigorously for at least one hour before, or any time during the test.
  4. The patient SHOULD NOT smoke for at least ½ hour before collecting any air-sample used for the test.
  5. The patient SHOULD notify (or remind) the Doctor of any recent antibiotic treatment and/or runny diarrhea, since those conditions can also affect the validity of the test.



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