Lactose intolerance test


Lactose tolerance test

A normal response to 50 grams of lactose is a rise in the plasma glucose of greater than 1.2 mmol/L.

The most common cause of lactose intolerance is "acquired lactose intolerance of the adult", which is actually a native physiological condition in which the brush border disaccharidase lactase is lost in the adult.

European populations have a relatively low incidence of the above and hence reduction of gastro-intestinal lactase activity in the adult is considered to be a pathological condition (it is obviously much more serious in the infant). Lactose intolerance develops in a variety of gastro-intestinal conditions in which the integrity of the intestinal mucosa is compromised.

N.J.Miller FRCPath

October 2002

Patient Instructions:

Fast from midnight the previous evening.

Appointment Notes:

Test takes 2.5 hours and patient should fast from midnight the previous evening.

Sample Requirements:

Collect a fasting blood sample into a fluoride oxalate blood tube. Give the patient 50 grams of lactose dissolved in water and collect further fluoride oxalate samples at 30 mins, 1hr, 1.5hrs, 2hrs & 2.5 hrs. Label each sample with the time it was taken & patient name.

Postal Samples Acceptable:


For further details please contact the laboratory at: