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3 Day Parasitology testing versus Faecal Multiplex PCR testing

3 Day Parasitology vs Faecal PCR: What’s best for your patient


Australian Clinical Labs Functional Pathology are proud to offer an extensive range faecal stool testing for Doctors and other health practitioners. From assessing the microbiome of the gastrointestinal tract to detecting parasites and other harmful bacteria, our offering is dedicated to specialist testing tailored to patient symptoms.

We frequently receive questions from our practitioners asking us to explain the differences between 3 Day Parasitology testing and Faecal Multiplex PCR Testing in order to determine:

  • Which one is best for their patient
  • The pros and cons of each test

Addressing these questions early in the process of assessing a patient may make all the difference to a patient’s diagnosis and response to treatments or therapies.

Clinical Labs Functional Pathology Laboratory Operations Manager, Kirstie McLaren, and Technical Support officer and Naturopath, Jasmine King, offer some valuable information surrounding these different types of GIT testing to further practitioner understanding.

     1. 3 Day Parasitology

Clinical Labs Functional Pathology use gold standard testing methodology to detect parasitic infection. Our testing combines faecal concentration and manual microscopy techniques for easier detection. The concentration technique essentially filters the parasite eggs out of the other faecal material. The concentrated sample is strained and examined under a microscope by highly trained scientists. It is important to note that although this is considered the gold standard, this method involves manual screening of samples and is subject to human error. This method also relies on a higher number of eggs present in the sample for detection using the microscope.

3 Day Parasitology testing offered through Clinical Labs Functional Pathology is proven to be a more effective method of parasitic screening than a single sample parasite test. The concentration of eggs of different parasites shed into the faeces varies according to:

  • Lifecycle of individual parasite(s) present
  • Gut transit time of an individual patient (a patient who has frequent bowel motions is likely to be flushing parasites through their system rapidly, therefore there is a smaller concentration to be found in any single faeces samples collected at a point in time).

In order to overcome these variables, Clinical Labs offers testing options that involve performing faecal. To ensure human error is reduced to an absolute minimum, Clinical Labs scientists are highly trained and participate in external Quality Assurance programs for faecal testing as part of Clinical Labs’ ongoing NATA accreditation. These programs include a module specific to parasitic detection utilising the concentration technique. Staff trained in faecal concentration microscopy are required to participate in these modules regularly and additionally undergo annual competency reviews to formally monitor the performance of individuals.  This ensures consistent quality results are reported for all Clinical Labs patients.

     2. Faecal PCR

With the relatively recent introduction of Faecal Multiplex PCR testing, there has been an increase in the rates of detection of parasites. PCR testing is an extremely sensitive detection methodology, as it only requires a small amount of parasite DNA to be present in the faecal sample for a positive result. PCR testing does not require intact or viable parasites for detection, and can often report a positive result even after a successful eradication therapy as “dead” organisms are shed into the faeces which have detectable intact DNA fragments. PCR technique is also very specific, so will only detect the specific parasite that it has been set to detect. This can also be a negative, as if the PCR assay does NOT include primers to a specific parasite or genetic variant of a parasite, it will not be detected.

Therefore a combination of microscopy and PCR can be of benefit.  Most PCR assays available in the market today test only for a limited number of parasites, whereas a trained microscopist is capable of detecting a large range of parasites (much larger than any current Parasite PCR test on the market).


To learn more about gastrointestinal testing click here. Alternatively, for more information call the Functional Pathology team on 1300 55 44 80.