Background: 

Parasitology laboratory routine diagnosis involves traditional morphological identification of parasites by microscopy and staining. Recently, molecular methods are increasingly used by more laboratories to enhance the identification of parasites. The demand to start a proficiency testing program is due to the emergence of these molecular methods in the absence of an existing QAP and, in part because of the need for faster reporting and diagnosis. In response to this, The RCPA Quality Assurance Programs developed a pilot survey to assess the detection and identification of gastrointestinal parasites.

Materials/methods:

The first pilot study of the gastrointestinal parasites module included six simulated clinical specimens:

• Two samples were prepared in fixed stool and washed three times with saline, one contained Giardia species and Cryptosporidium species (A) whilst the other had Dientamoeba fragilis (C).
• One negative that contained only a faecal matrix (B).
• One was a commercial sample of Entamoeba histolytica (D).
• Two fresh stool samples with DNA stabiliser had Blastocystis hominis (E) and Giardia species (F) respectively.

Graphs and tables were used to show results according to the methods and investigations used by the participants.

Results:

Across the 28 participating laboratories from Australia and globally, the results were returned as follows:

• Two participants reported D. fragilis on the sample that had Giardia species and Cryptosporidium species (A) whilst 26 participants reported “no parasites detected”.
• D. fragilis (C)was correctly reported by one participant whilst 27 reported “no parasites detected”.
• The negative sample (B) was reported as “no parasites detected” by all participants (100%).
• Twenty-seven (96%) participants reported Entamoeba histolytica (D).
• Nine participants reported B. hominis (E) present.
• Twenty-eight (100% concordance) participants reported Giardia intestinalis (F).

Five participants used in-house assays, whilst the remaining 23 used six different commercial amplification/detection platforms. PCR assay controls (inhibition, negative and positive) were employed by fourteen (50%),12 (43%) and 14 (50%) participants respectively.

Conclusion:

The molecular gastrointestinal parasite pilot module QAP had enabled participating laboratories to review the pre-analytical, analytical and post-analytical stages of their molecular testing protocols. This also created a positive effect on participants by influencing changes and updates to their assays, algorithms and reporting protocols.