Scientific Opinion on Analytical sensitivity of approved TSE rapid tests

Scientific Opinion on Analytical sensitivity of approved TSE rapid tests Question number: EFSA-Q-2009-00687 Adopted: 10 December 2009 Summary (32 KB)

http://www.efsa.europa.eu/en/scdocs/doc/s1436.pdf


Opinion (417 KB)

http://www.efsa.europa.eu/en/scdocs/doc/1436.pdf


Annex – Report of the CRL study (762 KB)

http://www.efsa.europa.eu/en/scdocs/doc/1436ax1.pdf


Summary

Following a request from the European Commission, the Panel on Biological Hazards (BIOHAZ Panel) was asked to deliver a scientific opinion on Analytical sensitivity of approved TSE rapid tests.

In 2008 the European Commission asked the Community Reference Laboratory (CRL) for TSEs to assess the analytical sensitivity for all the currently approved TSE rapid tests in order to produce robust analytical sensitivity data and evaluate each test against the same sample sets for the three main types of ruminant TSE: BSE, Classical scrapie and Atypical scrapie. The European Commission forwarded the final report of the study (CRL study) to EFSA and requested EFSA to provide a scientific evaluation of it and, if needed, based on the information available in the CRL report, reconsider and amend previous recommendations related to the approval of each of those rapid tests, based on the requirements as set in the current EFSA protocols for the evaluation of TSE rapid post mortem tests.

The current scientific opinion gives an overview of the methodology and results of the CRL study. The CRL study investigated the analytical sensitivity of all the approved TSE rapid tests and also investigated the stability of Atypical scrapie positive samples when stored frozen at -80°C. The BIOHAZ Panel acknowledges that for the first time all the tests were evaluated against the same sample set, allowing a direct comparison of their analytical sensitivity and concludes that the study findings provide valuable information in determining the continued suitability of tests currently used for TSE monitoring in the EU.

With regard to the BSE analytical sensitivity study performed by the CRL, the BIOHAZ Panel concludes that AJ Roboscreen BetaPrion®, Bio-Rad TeSeETM SAP, Enfer TSE v2, Enfer TSE v3, IDEXX HerdChek Standard, IDEXX HerChek Short, IDEXX HerdChek Ultra Short, Roche Prionscreen and Prionics®-Check Western performed within a maximal 2 log10 inferiority range as compared to the most sensitive test system. Prionics®-Check LIA and Prionics®-Check PrioSTRIP gave unexplained and unresolved specificity problems which hamper the interpretation of their analytical sensitivity and the comparison with other approved tests. Therefore the BIOHAZ Panel recommends that the analytical sensitivity of Prionics®-Check LIA and Prionics®-Check PrioSTRIP should be re-assessed by appropriate experiments under the supervision of the CRL. Excluding Prionics®-Check LIA and Prionics®-Check PrioSTRIP, for all other tests no potential differences in field detection performance can be inferred on the sole basis of the difference in analytical sensitivity reported in this study.

With regard to the Classical scrapie analytical sensitivity study performed by the CRL, the BIOHAZ Panel concludes that all tests (Bio-Rad TeSeETM SAP, Bio-Rad TeSeETM Sheep/Goat, Enfer TSE v2, Enfer TSE v3, IDEXX HerdChek Standard, IDEXX HerdChek Short, IDEXX HerdChek Ultra Short, Prionics®-Check LIA SR, Prionics®-WB Check Western SR) performed within a maximal 2 log10 inferiority range as compared to the most sensitive test system. Marginal specificity problems were observed with Prionics®-Check LIA SR and Enfer TSE v3 with sheep samples, which did not compromise the estimation of their analytical sensitivity. No potential differences in field detection performance can be inferred on the sole basis of the difference in analytical sensitivity reported in this study.

With regard to the Atypical scrapie stability study, the BIOHAZ Panel concludes that an apparent decrease in the detected signal could be observed during the stability study and that this was taken into account in the study.With regard to the Atypical scrapie analytical sensitivity study performed by the CRL, the BIOHAZ Panel concludes that Bio-Rad TeSeETM SAP, Bio-Rad TeSeETM Sheep/Goat, IDEXX HerdChek Standard, IDEXX HerdChek Short and IDEXX HerdChek Ultra Short performed within the maximal 2 log10 inferiority range as compared to the most sensitive test system. It is also concluded that Enfer TSE v2, Enfer TSE v3, Prionics®-Check LIA SR and Prionics®-WB Check Western SR could fail in identifying field Atypical scrapie cases that other validated tests would detect. The EFSA protocol for the evaluation of rapid post mortem tests to detect TSE in small ruminants states that tests that are not able to meet requirements for all types of TSE agents on known positive samples should not be considered for testing in the field. Consequently, and based on the information obtained from the CRL study, Enfer TSE v2, Enfer TSE v3, Prionics®-Check LIA SR and Prionics®-WB Check Western SR cannot be recommended for use for TSE monitoring in small ruminants.

The BIOHAZ Panel recommends that a similar study should be conducted with samples of Atypical BSE (BSE-L, BSE-H) and of sheep BSE, if material is made available to the CRL for TSE. Finally it is also recommended that, if feasible, samples of Atypical BSE, sheep BSE, Classical scrapie and Atypical scrapie should be included in the batch release testing procedure.

Published: 18 December 2009


http://www.efsa.europa.eu/en/scdocs/doc/s1436.pdf




SCIENTIFIC OPINION

Scientific Opinion on Analytical sensitivity of approved TSE rapid tests1 EFSA Panel on Biological Hazards (BIOHAZ)2, 3 European Food Safety Authority (EFSA), Parma, Italy ABSTRACT The Community Reference Laboratory (CRL) for TSEs studied the analytical sensitivity for all the currently approved TSE rapid tests in order to produce robust analytical sensitivity data and evaluate each test against the same sample sets for the three main types of ruminant TSE: BSE, Classical scrapie and Atypical scrapie. This opinion provides a scientific evaluation of the CRL analytical sensitivity study, based on the requirements as set in the current EFSA protocols for the evaluation of TSE rapid post mortem tests. It is concluded that the CRL study findings provide valuable information in determining the continued suitability of tests currently used for TSE monitoring in the EU. Conclusions on the performance of the approved rapid tests within the CRL study are included. On these bases a number of tests cannot be recommended for use for the monitoring of BSE in cattle and TSE in small ruminants in the EU. Finally, the BIOHAZ Panel recommends that a similar study should be conducted with other types of TSE in cattle and small ruminants.


KEY WORDS BSE, Classical scrapie, Atypical scrapie, analytical sensitivity, TSE rapid tests. 1



http://www.efsa.europa.eu/en/scdocs/doc/1436.pdf



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