Lactose Tolerance Test

The lactose tolerance test is a medical procedure used to diagnose lactose intolerance, a condition in which the body is unable to digest lactose, a sugar found in milk and other dairy products.

Purpose

The purpose of the lactose tolerance test is to measure the body's ability to digest lactose and absorb its components, glucose and galactose.

Procedure

The procedure involves the following steps:

• The patient fasts for 8-12 hours before the test to ensure that the digestive system is empty.
• A baseline blood sample is taken to measure the patient's blood glucose level.
• The patient is then given a lactose-containing drink, usually a sugary solution containing 50-100 grams of lactose.
• Blood samples are taken at regular intervals (usually 30 minutes, 1 hour, and 2 hours) after the lactose drink is consumed to measure the patient's blood glucose level.
• The patient may also be asked to collect a stool sample or undergo a breath test to measure the amount of hydrogen in their breath, which can indicate the presence of undigested lactose in the colon.

Interpretation of Results

The results of the lactose tolerance test are interpreted as follows:

• A normal result is indicated by a rise in blood glucose level after consuming the lactose drink, which shows that the body is able to digest and absorb lactose.
• An abnormal result is indicated by little or no rise in blood glucose level, which suggests that the body is unable to digest lactose properly.
• A low blood glucose level or a high level of hydrogen in the breath may also indicate lactose intolerance.

Risks and Complications

The lactose tolerance test is generally a safe procedure, but it may cause some discomfort, such as:

• Bloating and gas
• Diarrhea
• Stomach cramps
• Nausea and vomiting

Precautions

Certain precautions should be taken before undergoing a lactose tolerance test, including:

• Telling the doctor about any medications being taken, as some may affect the results of the test.
• Avoiding eating or drinking anything except water for at least 8 hours before the test.
• Informing the doctor about any medical conditions, such as diabetes, that may affect the results of the test.