syzygy
September 2014
Hydrogen and Methane Breath Testing — Dr David Kanowski, Biochemistry
Hydrogen and methane breath testing is a non-invasive procedure
that can be used in the diagnosis of disorders of sugar and
carbohydrate malabsorption, and also of small intestine bacterial
overgrowth (SIBO).
The test relies on the fact that hydrogen and methane are not
produced by any metabolic pathway in the body. These gases are
only produced by the action of enteric bacteria on unabsorbed
carbohydrates or sugars. When unabsorbed sugars reach the colon
(or distal small intestine in the case of SIBO), bacterial fermentation
produces hydrogen, which is readily absorbed through the wall of
the bowel and then expired in exhaled air, where its concentration
can be measured. In 15-30% of the population, the gut flora contain
significant levels of Methanobrevibacter smithii. In these individuals,
most of the hydrogen is converted into methane by the bacteria.
Measurement of both gases is necessary to avoid the underdiagnosis of sugar malabsorption.
At Sullivan Nicolaides Pathology, analysis of the expired gases
is performed using a GastroCH4ECK analyser. This analyser
also measures the oxygen content of each sample to allow for
correction of gas concentrations where there has been variability in
collection, for example, when patients do not adequately produce
an end-tidal breath sample. It has become apparent that patients
are very variable in their ability to produce a good breath sample,
so uncorrected gas levels may significantly underestimate the
concentration being exhaled.
Test procedure
Patients must adhere to a low-fibre diet for two days prior to the
test, as unabsorbed complex carbohydrates can significantly elevate
the baseline hydrogen and methane levels. This is followed by an
overnight fast for at least 14 hours prior to the test. Ideally, the
patient should also empty their bowels on the morning of the test,
as failure to do this may significantly elevate basal methane levels.
After the collection of a baseline gas sample, a standard dose of the
test sugar is consumed by the patient. End-tidal breath samples are
collected at 0 (basal), 20, 40, 60, 90 and 150 minutes.
The table below lists the test substances available for the hydrogenmethane breath test at SNP. Selection of the most appropriate
challenge test may require a detailed dietary history to determine the
likely foodstuff that is causing symptoms.
Many patients with irritable bowel symptomatology may respond
to the FODMAP (Fermentable Oligosaccharides, Disaccharides,
Monosaccharides and Polyols) diet. Testing for the likely culprit
food-stuff can assist in diagnosis and means that the appropriate
diet may be less rigorous.
Sugar
Food source
Condition
Test dose
Lactose
Milk
Lactose intolerance
25g
Fructose
All fruits, many vegetables, processed foods
Fructose malabsorption
25g
Sucrose
Common natural sweetener
Sucrase-isomaltase deficiency (rare), GIT inflammation, SIBO
50g
Maltose
Starchy foods
Sucrase-isomaltase deficiency (rare), GIT inflammation, SIBO
50g
Sorbitol
Stone fruits, sugar substitute in gums and processed foods
Sorbitol malabsorption
5g
Mannitol
Some vegetables (mushrooms, cauliflower), also a food
additive
Mannitol malabsorption
5g
Glucose
Most fruits, derived from starch in diet
GIT inflammation, SIBO
50g
Lactulose
N/A
SIBO
20g
Hydrogen and Methane Breath Testing cont
Clinical interpretation of the breath test
A positive response indicates that the particular test foodstuff was not absorbed normally. This interpretation is made if there is an increase
of > 20 ppm in breath hydrogen or > 12 ppm in breath methane. With a relatively normal gut transit time, this typically occurs between 60
and 90 minutes after the test dose.
An early increase (i.e. within 30 minutes) may indicate the presence of SIBO. There is still debate in the literature as to whether the glucose
or lactulose challenge is more appropriate for detecting SIBO.
High baseline levels, particularly of methane, can indicate poor dietary preparation. This can also be associated with constipation or
intestinal diverticular disease.
An interpretive comment is always provided with this test, so it is not necessary to be familiar with the guidelines to interpret patient test
results.
WHAT TO REQUEST
HBT + clinical notes with detailed dietary history
About the Author − Dr David Kanowski FRCPA
Dr David Kanowski is a graduate of The University of Queensland,
where he completed an honours degree in biochemistry before
studying medicine. After graduating in 1985, and a short period in
the UK studying anaesthetics, he returned to Brisbane to train in
chemical pathology. David joined Sullivan Nicolaides Pathology in
1997.
TEST PREPARATION
Patient collection instruction note available (Item 47860)
WHERE TESTS ARE PERFORMED
Only at SNP procedural centres,
see: www.snp.com.au/locations/collectioncentres
COSTS
Medicare rebate + $120 ($60 for concession card holders)
Dr Kanowski is available for consultation.
T: (07) 3377 8779
E: [email protected]
Faecal Preservative Kits: going, going, gone – Dr Jenny Robson, Microbiology
Faecal PCR now replaces stained faecal smears for Dientamoeba fragilis and Entamoeba species
In the past, Sullivan Nicolaides Pathology has supplied faecal preservative kits in order to improve the
detection of fragile flagellated parasites such as Dientamoeba fragilis, and the morphology of the various
protozoan Entamoeba species. Without the routine use of permanently stained faecal smears, these parasites
are notoriously difficult to detect.
These faecal preservative kits contain sodium acetate-acetic acid-formalin (SAF) which preserved parasite
morphology and allowed easier detection by microscopy if there were delays in specimen receipt. With the
advent of Faecal PCR this is no longer necessary. The DNA from any faecal parasites present is much more
robust and easily detectable.
The current Faecal Enteropathogen PCR test menu includes 5 bacteria (Salmonella, Campylobacter, Shigella,
Yersinia and Aeromonas) and 5 parasites (Blastocystis spp., Dientamoeba fragilis, Cryptosporidium spp.,
Giardia lamblia and Entamoeba histolytica).
Formally seldom detected by faecal microscopy, the prevalence of D. fragilis has increased from 0.6% to
16.4% using PCR in our laboratory. The pathogenicity of this organism is the subject of ongoing debate. This
relates mainly to the predicament around decisions about treatment that are still to be defined.
Because primers and probes are directed towards the virulence factors for E. histolytica var histolytica nonpathogenic E. histolytica var histolytica is no longer of concern to differentiate.
When Dientamoeba fragilis or Entamoeba species are suspected, please request Faecal PCR with
M/C/S. SAF preservative kits are no longer required.
Dientamoeba fragilis
E. histolytica var histolytica
We deliver cardiovascular
services to regional and
remote Australians
Australians living outside capital cities are at significantly greater risk (26%) of the
nation’s biggest killer, cardiovascular disease (CVD), according to recent data released
by the National Heart Foundation of Australia.
One in four people living in regional and rural areas is suffering from the disease,
compared to one in five in metropolitan areas, with access to services being
highlighted as a major reason.
SNP’s Cardiology Services team is committed to increasing the accessibility of cardiac
testing to regional and remote areas, providing 24- and 48-hour Holter monitoring and
24-hour ambulatory blood pressure monitoring all over Northern NSW, regional QLD
and NT.
SNP is now also offering a comprehensive ECG service. ECGs are read in real-time.
They are authorised and reported by a senior Sonic Healthcare cardiologist. If you
are interested in this service being close to your practice, please call our Cardiology
Services team on (07) 3377 8758.
To find your nearest cardiology-enabled collection centre please visit: www.snp.
com.au/locations/collectioncentres and filter by either Holter, ABP or ECG.
Our new brochure demystifies STI testing to help
at-risk patients take action
Dr Jeanine Bygott, Microbiology
Sullivan Nicolaides Pathology has produced a brochure for
our GPs to have on hand to help facilitate a dialogue about
STI testing with at-risk patients.
GPs are at the front line as the main providers of sexual
health services. Understandably many patients, young men
in particular, are reluctant to start a conversation about
sexual health. This booklet sets out to explain and demystify
STI testing and encourages people to take control and get
tested, particularly in the context of rising rates of sexually
transmitted infections and the frequent lack of symptoms.
To help make testing less confronting, the booklet describes
what the patient can expect — what samples are used, how
they are collected, when testing should take place and when
results can be expected. The key message is that testing is
easy, confidential and free.
We hope that this booklet will have a place in helping to
instigate STI testing in young at-risk patients.
Copies can be ordered through SNP doctors’ stores
(Item 11897) or by contacting your Medical Liaison Manager
on 1300 SNPATH (1300 767 284)
DISCLAIMER
The images used in this brochure are for illustrative
purposes only. They are from stock libraries and the
people portrayed in them are models. In no way is it
suggested that these people have health problems.
Did you know that STI testing can be done from
ThinPrep® Samples?
STI testing can be done opportunistically when patients present
for a Pap smear. If using ThinPrep® liquid-based cytology (LBC) for
Pap testing, then PCR testing for STIs can be done from the same
ThinPrep® vial. Chlamydia, gonorrhoea and trichomonas PCR testing
from ThinPrep® specimens are all TGA approved. This obviates the
need for sending further specimens or swabs for STI detection.
Screening of at-risk patients is important, particularly in the context of
rising rates of STIs. Although chlamydia is the most frequently notified
STI in Australia, gonococcal infection is on the rise. For instance, the
rate of gonorrhoea diagnosis has increased by almost 70% from
2008 to 2012 (Kirby Report, 2013). Simultaneous PCR testing
for chlamydia and gonorrhoea is now performed on our Roche 4800
platform: ThinPrep® specimens are suitable, in addition to genital
swabs and urine.
There is a fundamental change afoot in Pap testing, and LBC methods
such as ThinPrep® will likely be utilised in the future for HPV PCR
screening. (Current Medicare funding and NHMRC guidelines only
recommend high-risk HPV PCR testing for 'test of cure' following
treatment of high-grade intraepithelial cervical lesions). Until these
changes are implemented, likely in 2016, 2-yearly Pap tests should be
continued and used as an opportunity to consider concomitant STI
screening.
About the Author − Dr Jeanine Bygott FRCPA
Dr Jeanine Bygott trained in Medical Microbiology and Virology at Cambridge University Hospital, UK. Jeanine has
extensive experience in tropical medicine, having worked for several years at a tropical medicine clinic in Ireland. She
also studied parasitology under Prof. Peter Chiodini at the Hospital for Tropical Diseases, London. Jeanine joined SNP
in 2008.
Dr Bygott is available for consultation. T: (07) 3377 8402
E: [email protected]
Doctors’ Education Library Update
Our pathologists and senior scientists have been active on the speaking circuit these past weeks.
Five recorded seminars have been added to our Doctors’ Education Library.
Dr Nick Musgrave — Familial Colon Cancer (Polyposis Syndromes and Lynch Syndrome)
Dr Jenny Robson — Brucellosis (Brucellosis: animals or humans as sentinels?)
Professor David Weedon — Intraepidermal Vesiculobullous disorders (The anatomical level of the split
and the mechanisms responsible to assist in diagnosis)
Professor David Weedon — the Lichenoid Reaction Pattern
Dr Blake O'Brien — Granulomatous Reaction Patterns. (Four types of granulomas are covered –
sarcoidal, tuberculoid, necrobiotic & suppurative)
Downloading
instructions
Step 1
Go to the iTunes App Store,
type in Sonic Dx, tap on the
icon to download, and install
the app.
Step 2
Open the Sonic Dx app.
Simple fast intuitive mobile results
Viewing online pathology results just got
a whole lot more intuitive
Here at Sullivan Nicolaides Pathology we’ve just released our much-anticipated
new pathology results app – Sonic Dx.
Sonic Dx is a feature-rich app that is intuitive and easy to use. It has been developed in close
consultation with clinicians and pathologists to provide you with quick access to your patient
results, when and where you need them. It also has enhanced functionality that allows you to track
specific patients and securely email results directly to a colleague or patient.
Sonic Dx replaces Webster Mobile as our mobile results app. Webster desktop will continue to
function as usual in the short-term, but will be transitioned to Sonic Dx over the next few months.
Doctors who have an existing Webster account can access Sonic Dx on their mobile device using
their Webster ID and password. It is simply a matter of downloading the app from the iTunes Store,
entering your existing Webster username and password, selecting your pathology practice, and
you’re ready to go. (If you do not have your username and password, please go to
sonicdx.com.au/register or email [email protected]
Step 3
Enter your current Webster
username and password,
select your practice, and tap
Login.
Sonic Dx is available on iPhone and iPad and will soon be released on Android.
If you are an iPhone or iPad user and you would like a copy of the How-to brochure and icon
glossary, please contact your Medical Liaison Manager on 1300 SNPATH (1300 767 284).
SULLIVAN NICOLAIDES PTY LTD • ABN 38 078 202 196 • A subsidiary of Sonic Healthcare Limited • ABN 24 004 196 909
134 WHITMORE STREET • TARINGA • QLD 4068 • AUSTRALIA •TEL (07) 3377 8666 • FAX (07) 3870 0549
PO BOX 344 • INDOOROOPILLY • QLD 4068 • AUSTRALIA
www.snp.com.au
Syzygy—now on 100% recycled paper.
Meridio 117452 September 2014
Correct at time of publication
© Sullivan Nicolaides Pty Ltd 2014