The Tests

Stream Diagnostics have been providing simple, accurate and non-invasive tests for fructose malabsorption, Lactose and Sorbitol malabsorption and Small Intestine Bacterial Overgrowth SIBO around Australia for many years.

These tests are conducted 'in-clinic' or can be provided to patients via a 'Home Kit', enabling them to complete their tests in the comfort of their own home.

When your tests are completed, you will need to consult with an Accredited Practicing Dietitian - who can guide you to make dietary changes to minimise any symptoms you experience.

Lactulose Control Test

The use of the Lactulose Control Test, the hydrogen/methane diagnostic units, and the specific time frames of these tests are the result of at least 5 years of research by Monash University’s Department of Medicine. This research has determined that the Lactulose Control Test should be performed in advance of any other sugar tests (Fructose, Lactose, Sorbitol, Glucose).

The Lactulose Control Test is used to set the ‘baseline’ response of each patient’s unique physiology. The Lactulose test is compulsory and must be performed with any other tests within a one month time frame.

The Lactulose test is used:

  • To assess the duration of breath monitoring in subsequent tests.
  • To assess the patient’s level of hydrogen and methane production in order to cross-reference with subsequent sugar tests.
  • To determine whether glucose test is needed to confirm the presence of small intestine bacterial overgrowth (SIBO).

Some clinics offer sugar malabsorption testing using hydrogen-sensing equipment only, as well as not performing the Lactulose Control Test in relation to any other sugar tests performed.

This presents a number of challenges with regards to your results.

If these tests are performed on a hydrogen-only machine, without a Lactulose Control Test, and the patient creates very low numbers, there is no calibrative mechanism by which to evaluate the subsequent sugar tests.

The handheld breathalyser-type (hydrogen only) diagnostic units are considerably less costly than the methane and hydrogen units, and for this reason a number of centres provide this type of testing, as it is cheaper to set up. Furthermore, they yield less sensitive data which compromises the results. The hydrogen/methane units and the protocols used by Stream Diagnostics ensure greater accuracy.

In many instances, test centres using these hydrogen-only devices will charge the same fee or more for each test as centres providing hydrogen and methane sampling on the latest diagnostic units available.

For these reasons it is of considerable importance to have all your sugar malabsorption tests performed on diagnostic units which measure Methane and Hydrogen simultaneously.

Stream Diagnostics does not use, nor has ever used, these cheaper hydrogen-only units. We only use the considerably more expensive and accurate hydrogen/methane units, which are considered the “gold standard” for this type of analysis.

With the exception of the Glucose test (which has a duration of 120 minutes), the Lactulose, Fructose, Sorbitol and Lactose tests run between 2.5 - 3 hours. As the time required for each of these tests can differ for each patient, you should allow for 3 hours on each visit.

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Fructose Test

This is used to determine if patient has fructose malabsorption.

Fructose is a single-molecule sugar (monosaccharide) which approximately 30% of the population cannot fully absorb.

If this sugar is not absorbed via the small intestine, it will travel through to the large bowel. If the ‘healthy’ bacteria present in the large bowel feed on this excess fructose, this can cause a range of symptoms such as diarrhoea and/or constipation, bloating, stomach noises (borborygmi), increased and foul-smelling flatulence, lethargy and headaches. There are people with malabsorption who are asymptomatic (experience no symptoms at all).

Patients are provided with a diet which they must follow 2 full days before this test to decrease the level of bacterial activity in their gut. This creates a type of controlled environment in relation to dietary sugars. When patient arrives for test, they create a baseline breath sample, which records their post-diet and pre-sugar drink breath reading for hydrogen and/or methane.

Then they have the sugar drink, followed by successive breath readings every 20 minutes for the next 2 hours at minimum. If malabsorption of Fructose is taking place in the intestinal system, bacteria will begin to break down the sugar, converting some of it into increased hydrogen and/or methane readings via the breath samples.

It is the degree of change in these readings between the first ‘baseline’ breath sample and successive samples taken after the sugar drink, which can indicate if Fructose malabsorption is an issue for this patient.

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Lactose Test

This is used to determine if patient has lactose malabsorption (commonly referred to as ‘lactose intolerance’).

Lactose is a double-molecule sugar (disaccharide) comprised of one Glucose and one Galactose molecule, which requires the presence of an enzyme – Lactase – to break apart the two molecules so the resulting single molecules of Glucose and Galactose can be absorbed.

If the intestinal system does not have enough Lactase enzyme to divide the lactose, it will travel through to the large bowel. If the ‘healthy’ bacteria present in the large bowel feed on this excess lactose, this can cause a range of symptoms such as diarrhoea and/or constipation, bloating, stomach noises (borborygmi), increased and foul-smelling flatulence, lethargy and headaches.

There are people with malabsorption who are asymptomatic (experience no symptoms at all).

Patients are provided with a diet which they must follow 2 full days before this test to decrease the level of bacterial activity in their gut. This creates a type of controlled environment in relation to dietary sugars. When patient arrives for test, they create a baseline breath sample, which records their post-diet and pre-sugar drink breath reading for hydrogen and/or methane.

Then they have the sugar drink, followed by successive breath readings every 20 minutes for the next 2 hours at minimum. If malabsorption of Lactose is taking place in the intestinal system, bacteria will begin to break down the sugar, converting some of it into increased hydrogen and/or methane readings via the breath samples.

It is the degree of change in these readings between the first ‘baseline’ breath sample and successive samples taken after the sugar drink, which can indicate if Lactose malabsorption is an issue for this patient.

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Sorbitol Test

This is an important FODMAP sugar to test for, in conjunction with Fructose and Lactose.

Research has found that sorbitol malabsorption is prevalent in the healthy population with 90% of people having sorbitol malabsorption. Also, this study has shown that a high percentage (approx 53%) of the IBS* population have sorbitol malabsorption (unpublished data). Because it is found so commonly in fruits, plus is increasingly being used in "sugar-free" products, sorbitol consumption can therefore cause unwanted gastrointestinal symptoms in both healthy subjects and patients with IBS.

The following are foods which contain sorbitol: Apple, Apricot, Avocado, Beans (green), Blackberry, Bok Choy, Broccoli, Cabbage (common),Capsicum (green), Cherries, Chutney, Clingstone Peach, Coconut Cream, Coconut Milk, Coconut (shredded, dried), Corn on the cob, Dried Apple, Dried Apricots, Dried Pear, Eggplant, Fennel Tops, Lychee, Nashi, Nectarine, Peach (yellow), Peach (white), Pear - Packham (firm, peeled), Pear - Packham (ripe, peeled), Prunes, Raisins, Rice flakes with Psyllium (gluten free), Wasabi, Muesli, Muesli (gluten, wheat, dairy, peanut free), Mushrooms, Turnips.

Many of these foods, particularly the fruits, will have excess fructose also. This is why it's important to test for which carbohydrate is actually provoking symptoms, or if it's both.

You don't want to eliminate all fructose foods if it's the sorbitol causing the problem, and you also want to be informed if both Sorbitol and Fructose malabsorption are present, in order to properly manage food intake.

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Glucose Test

This is used to indicate if Small Intestine Bacterial Overgrowth might be present.

If Small Bowel Intestine Overgrowth (SIBO) is suspected, two tests must be performed. The Lactulose Control Test, followed by the Glucose Test. Other tests can be performed along with the Lactulose and Glucose tests (eg: Fructose, Lactose, Sorbitol), to assess the malabsorption of these other sugars as well.

Small Intestine Bacterial Overgrowth may occur if the population of bacteria increases due to the excess food source provided by lactose and/or fructose not being absorbed in the small intestine (other causes can be due to illness). These excess bacteria may migrate to the small intestine, generating similar symptoms as fructose, lactose and/or sorbitol malabsorption.

Glucose is absorbed by the intestinal system, so if an elevated hydrogen and/or methane level is recorded during this test, it may indicate that bacteria are breaking down this sugar and converting it to this gas response in the patient’s exhaled breath.

A patient may have Fructose malabsorption, Lactose malabsorption and/or Sorbitol malabsorption and/or Small Bowel Bacterial Overgrowth at any given time. For this reason it is important to determine which of these conditions, if any, are present, so a course of action to decrease/manage the symptoms can be organised.

Stream Diagnostics provides the breath testing for these malabsorption issues. We cannot provide any form of dietary or medical guidance for treatment once your tests are completed. You will need to consult your existing practitioner, GP, Gastro Specialist, Specialist Dietitian for guidance on the use of the results in managing the symptoms of malabsorption.

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