How to Read a Lactose Tolerance Test
Definition
This is a exam that measures the ability of your intestines to assimilate lactose. Information technology is used to diagnose a deficiency of abdominal lactase (the enzyme used to assimilate lactose).
How the test is performed
In that location are several ways to perform this test. A typical procedure is described beneath, but exist sure to follow the specific instructions you receive.
After an overnight fast (no nutrient intake), y'all are given 50 grams of flavored liquid containing lactose to drink. After a defined menses of fourth dimension, tests are performed to determine whether your body tin break down the lactose and absorb information technology.
The preferred, non-invasive method is the measurement of breath hydrogen content. In this method, jiff samples are collected as you exhale. The exhaled gases are analyzed for hydrogen, a byproduct of bacteria that breakdown the lactose that is non absorbed.
If this test is non available, claret samples tin can be taken at various time to measure the amount of glucose, a product of lactose breakdown, in your blood. These blood samples are taken immediately prior to the test and then at various times after drinking the lactose solution (usually xxx, 60, and 120 minutes).
Blood Collection:
Blood is drawn from a vein on the inside of the elbow or the back of the paw. The puncture site is cleaned with antiseptic, and an elastic band is placed effectually the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with claret.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. One time the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
For an infant or young child:
The surface area is cleansed with clarified and punctured with a abrupt needle or a lancet. The claret may be nerveless in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a cast may be practical to the puncture site if in that location is any continued bleeding.
How to prepare for the test
Fast for 8 hours and avoid strenuous exercise for 8 hours before the exam.
For infants and children:
The grooming you lot can provide for this test depends on your child's age and experience. For specific information regarding how you lot can fix your child, come across the following topics:
- baby examination or process preparation (nascence to i year)
- toddler test or procedure grooming (1 to iii years)
- preschooler test or procedure training (3 to 6 years)
- schoolage test or procedure preparation (vi to 12 years)
- adolescent examination or procedure preparation (12 to 18 years)
How the test will feel
The breath sample is collected in either a special pocketbook or syringe, and should not exist associated with any pain or discomfort.
When the needle is inserted to draw blood, some people feel moderate hurting, while others feel only a prick or stinging awareness. Later, there may be some throbbing.
Why the test is performed
This test is used to diagnose lactase deficiency.
Lactose is a disaccharide (a type of sugar) in dairy products. During digestion, lactose is broken down into glucose and galactose, 2 simple sugars, by the abdominal enzyme lactase. Lactose-intolerant patients have a deficient or absent lactase enzyme. Bacteria metabolize the undigested lactose, producing gases such as hydrogen and other acid products.
Normal Values
In the breath test, a elevation ascension in hydrogen content of 12 parts per meg over the fasting (pre-test) level is considered positive.
In the blood exam, a rising in plasma glucose of more than than 30 mg/dl within 2 hours of ingesting the lactose is considered normal. A ascent of xx-30 mg/dl is inconclusive. A rise of less than 20 mg/dl is abnormal.
Note: mg/dl = milligrams per deciliter
What abnormal results mean
- Lactase deficiency
An aberrant exam should be followed by a glucose tolerance test to exclude an aberration in absorption of glucose earlier final that in that location is a lactase deficiency.
What the risks are
The risks associated with having blood drawn are:
- excessive bleeding
- fainting or feeling lightheaded
- hematoma (blood accumulating under the skin)
- infection (a slight risk any time the skin is broken)
- multiple punctures to locate veins
Special considerations
Veins and arteries vary in size from one patient to some other and from one side of the body to the other. Obtaining a blood sample from some people may exist more difficult than from others.
Terminal revised: December vii, 2012
by Mamikon Bozoyan, M.D.
Medical Encyclopedia
All ArmMed Media material is provided for data just and is neither communication nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your detail history for individual concerns.
Source: http://www.health.am/encyclopedia/more/lactose_tolerance_test/
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