Proficiency Tests

Purpose

An important function and duty of the European Union Reference Laboratory is to periodically organise comparative tests for National Reference Laboratories to assess their ability to identify the notifiable diseases and other current diseases. In this context it must be emphasised that inter-laboratory comparative tests are being carried out for various reasons such as:

  • to determine the capability of a laboratory to conduct specific diagnostic tests
  • to check or certify the performance of individual operators
  • to check or certify the calibration of instrumentation
  • to harmonise existing test methods
  • to evaluate new test methods
  • to assign values and ranges to standard materials
  • to resolve inter-laboratory differences

 

Proficiency tests in histopathology

Organisation

The European Union Reference Laboratory regularly organises proficiency tests for the detection of the listed and/or exotic parasites by means of histology. The goal of these proficiency tests is to establish that the examination of a given sample lead to the same conclusions in any laboratory within the European National Reference Laboratories network. Testing is based on an itinerant collection of hematoxylin and eosin stained histological sections of molluscs. Each participant receives slides with the name of the host species and has one week to read them and gives their results to the EURL. When all laboratories have read slides, a statistical analysis of the results is performed, based on the test of symetry (p value) and the kappa coefficient (k value). Subsequently, each participant receives a report on the test with identification of the content of the slides, and a summary of the results of all laboratories. The participants are informed of their own laboratory code number and are thus able to compare their performance with that of other laboratories.

European proficiency tests already organised in histopathology

Year

Host

Pathogens

1998

Ostrea edulis

Bonamia ostreae, Marteilia refringens

2001

Ostrea edulis

Bonamia ostreae, Marteilia refringens

Crassostrea gigas

Mikrocytos mackini,
Marteilioides chungmuensis

Crassostrea virginica

Haplosporidium nelsoni, H. costale, Perkinsus marinus

Ruditapes philippinarum

Perkinsus olseni

Saccostrea commercialis

Mikrocytos roughleyii

2002-2003

Crassostrea gigas

Mikrocytos mackini

Haplosporidium nelsoni

Ostrea edulis

Bonamia ostreae

Marteilia refringens

Mytilus edulis

Marteilia refringens

Ruditapes philippinarum

Perkinsus olseni

 2005

Ostrea edulis

Bonamia ostreae, Marteilia refringens

Crassostrea gigas

Mikrocytos mackini,
Marteilioides chungmuensis,
Haplosporidium nelsoni

2007

Ostrea edulis

Bonamia ostreae, Marteilia refringens

Crassostrea virginica

Haplosporidium nelsoni, H. costale, Perkinsus marinus

Crassostrea gigas

Mikrocytos mackini, Haplosoridium nelsoni

2009

Ostrea edulis

Bonamia sp., Marteilia sp.

Crassostrea gigas, C. virginica

Perkinsus sp., Mikrocytos sp., Haplosporidium sp.

2012

Ostrea edulis

Bonamia sp., Marteilia sp.

Crassostrea gigas, C. virginica

Perkinsus sp., Mikrocytos sp., Haplosporidium sp.

2014

Ostrea edulis

Bonamia sp., Marteilia sp.

Crassostrea gigas, C. virginica

Perkinsus sp., Mikrocytos sp.

Mytilus edulis, M. galloprovincialis

Marteilia sp.

Venerupis philippinarum, V. decussatus

Perkinsus sp., Mikrocytos sp.

2014 Histopathology proficency test

A new Inter Laboratory Comparison (ILC) test was organised in 2014 in order to test the competency of participants regarding the detection by histo cyto-pathology of the following pathogens : Bonamia sp., Marteilia sp., Perkinsus sp. and Mikrocytos sp. The test included one set of 30 histological slides and 10 scanned imprints available on the EURL website. The  30 H&E stained slides included 10 sections of flat oysters Ostrea edulis, 10 sections of cupped oysters (Crassostrea gigas and C. virginica), 5 sections of mussels (Mytilus edulis and M. galloprovincialis) and 5 sections of clams (Venerupis philippinarum and V. decussatus) .  The scanned slides included 5 digestive gland imprints and 5 gill imprints of flat oysters.  In total 21 participants registered and performed the test 2014-ILC-01. Results of this ILC are currently under analysis.

Proficiency tests in molecular biology

  • The 2008 proficiency test was devoted to the detection of  Bonamia ostreae by  PCR. The test included:
    1. the DNA extraction from gill tissue collected from 30 flat oysters, Ostrea edulis fixed in ethanol,
    2. the PCR test of these 30 samples using Cochennec et al. (2000) protocol.
  • The 2010 test was organised for the detection of Marteilia refringens by PCR-RFLP. The test included:
    1. the DNA extraction from tissue collected from 12 flat oysters Ostrea edulis and 12 mussels Mytilus edulis fixed in ethanol.
    2. the PCR test of these 24 samples using Le Roux et al. (2001) protocol see SOPs page.
  • The 2011 proficiency test was organised for the detection and quantification of herpes virus OsHV-1 in the Pacific oyster Crassostrea gigas by Real Time Polymerase Chain Reaction. The test included:
    1. the DNA extraction from 24 suspensions of ethanol-fixed mantle tissue of oyster Crassostrea gigas.
    2. the PCR test of these 24 samples using Real Time PCR (see protocol on the SOPs page).

In 2013, an Inter Laboratory Comparison (ILC) test was organised for the detection of Bonamia sp.in the flat oyster Ostrea edulis by Conventional Polymerase Chain Reaction (protocol available on the SOPs page). Optionally, the ILC aimed at comparing different PCR techniques for the detection of Bonamia sp. and the characterization of the species B. ostreae and B. exitiosa.  The test consisted of 24 ethanol fixed gill tissue suspensions including one positive control.

The report is available in the "NRL's section > Proficiency test > Result and reports" page (access limited to the European NRLs by login and password).