Guidelines for the submission of samples for confirmatory testing
The Animal and Plant Health Agency (APHA) will be happy to perform a confirmatory examination on your TSE suspect material. Please note and follow the submission instructions below.
Sampling
It is frequently possible to confirm a positive case of TSE using sub-optimal tissue. However, to be able to state conclusively that a case is TSE negative requires more stringent tissue collection and handling. Please refer to document How to take samples for TSE testing and confirmation.
For immunohistochemistry, for example, there must be good representation and preservation of the appropriate target areas; otherwise the only possible diagnostic outcomes are ‘confirmed’ or ‘not confirmed’. If sub-optimal tissue is submitted, only limited diagnosis may be possible.
Fresh material for confirmatory Western blot or SAF testing
Fresh, frozen caudal medulla is the optimal tissue requirement for either of these two tests. The sample should ideally be a minimum of 1-2g. However, a basic diagnostic WB can be performed on as little as 0.5g of tissue.
The material should be placed in sealed, clearly labelled containers. The containers should then be packaged with sufficient dry ice to remain frozen for the duration of the transit time, and in accordance with the IATA instructions (as below).
Fixed or paraffin-embedded material for immunohistochemistry
For histopathology and/or immunohistochemistry, fixed brain tissue (optimally the brainstem at the level of the obex, and cerebellum when available) should be submitted, either as ‘wet’ tissue, or as paraffin-embedded block(s). Detail should be given of the fixative used and any post-fixation treatment of the tissue.
Unstained sections
These can be sent if it is not possible to submit fixed or embedded material.
However, we frequently encounter difficulties with this type of submission if the bonding agent on the slides is not compatible with our staining protocols, and the likelihood of wash-offs is greatly increased.
Prior to dispatch
Prior to dispatch of any samples, please send an email to the TSEglobalNet mailbox:
Include preliminary information about the sample:
species
existing test results
amount and type of tissue being dispatched
proposed dispatch date and details
contact name and email
If you consider that any pathogen other than TSE might be present in the sample, please discuss this with us BEFORE sending the sample.
Packaging and labelling of parcels
All material must be packaged to IATA standards. It is recommended that you contact your nearest IATA office which will be able to give you the relevant local information with regard to pathogens, fixatives and dry ice.
The parcel should be clearly addressed to:
The Diagnostic Team
Building 96
APHA
Woodham Lane
Addlestone
Surrey
KT15 3NB
United Kingdom
Dispatch of parcels
It is requested that samples are sent to arrive on a working day (i.e. Monday to Friday), and not at a weekend.
Please note that all parcels should be dispatched in a way that ensures delivery to APHA, not just to the UK port of entry. If this is not done, samples will be delayed through customs clearance, and the sender will be invoiced for the costs incurred by this, and subsequent transport of samples to APHA.
Accompanying documentation
All samples must be accompanied by copies of relevant, current import and export Licences. You will be advised of any Import documentation required by APHA following your initial e mail. It is your responsibility to ensure that all relevant export documentation is in place before dispatch of any samples.
A letter with the individual animal and sample details and reference numbers, together with any relevant background information, should be included in the packaging. This letter should also include an indication of the test requested.
Costs and charging
For single or small numbers of cases APHA currently makes no charge (this service is presently covered by our role as an OIE reference laboratory).
However, if larger numbers of routine confirmatory tests are required over a period of time, this would be undertaken on a contractual basis, and a charge made. Please email the TSEglobalNet mailbox if you wish to discuss this option.
Under some circumstances transportation charges may be incurred (see above). These will be charged to the submitting laboratory.
Queries
If you require any further clarification of these procedures and options please email the TSEglobalNet mailbox: