Lactose Tolerance Test
Dietary lactose is hydrolysed to glucose and galacto= se by enteric mucosal lactase. Deficiency of the enzyme leads to lactose intolera= nce with symptoms after milk ingestion. Normally, the glucose formed as a result of hydrolysis of lactose will cause a rise in the serum glucose exceeding= 20 mG/dL over the fasting level. With lactase deficiency, the lactose tolerance curve will be flat, the glucose rise not exceeding 20 mG/dL over the fasting level. It is best to compare test results against a previous glucose tolerance test result.
During the 12 hours prior to the test the patient mu= st fast. Only limited quantities of water may be consumed during the 12 hour f= ast. Smoking and mild exercise are not permitted. Many drugs interfere with the = test results, they should be noted on the requisition= if taken within 3 days of testing.
A 100G solution of lactose is obtained from the phar= macy. The pharmacy should be notified at least 24 hours in advance whenever possi= ble. In children, the dosage of lactose is 2G/kG body weight.
The test is ordered as “Lactose Tolerance Test”.
A fasting glucose is drawn. This sample time and dat= e will be indicated on the sample label. The lactose solution is then administered orally. When the lactose load is ingested, the time is noted and specimen collection is timed from this point. Blood Glucose samples will be collecte= d at 1/2, 1, 2 hours after ingestion. Urine specimens are not required.
NOTE: The patient should not eat, drink or smoke dur= ing the test. Limited quantities of water may be consumed.
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Facility: Central Maine Med=
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