Why is Sentinel EAD more efficient than other health assessment methods?
The purpose of the EAD/PCR testing process is to provide researchers with the most thorough
and accurate rodent colony health assessment possible. There are other colony health
assessment solutions available (dirty-bedding sentinels, plenum swabbing, etc.) but recent testing
proves that they do not provide the same level of colony health monitoring as the Sentinel
EAD/PCR solution. In addition to the more accurate and thorough health assessments, the
Sentinel EAD method significantly reduces the amount of labor necessary to monitor colony health, and reduces the need for the use of sentinel animals.
Why is Sentinel EAD a better method than traditional Dirty-Bedding Sentinel programs?
Dirty-Bedding Sentinel Programs have been the gold standard for many years. However, it has
been well established that many agents do not transfer well using the traditional dirty bedding
Additionally, Dirty Bedding Sentinel Programs require much more labor, more materials and
require animals for use as sentinels. EAD/PCR is faster, easier, better, and meets the spirit of the
Why is Sentinel EAD a better method than plenum swabbing?
Plenum swabbing increases the accuracy of heath screening over dirty-bedding sentinel
programs, but is neither as labor-efficient nor accurate as Sentinel EAD/PCR. Its most
significantly drawback is its tendency of providing results based upon residual nucleic acid within
the IVC rack. The dust being swabbed from the plenum surfaces could be from legacy animals,
providing information on animals no longer housed on that rack. This is the main drawback of
sampling dust that has fallen out of the rack airstream. Allentown IVCs and how they manage
airflow help Sentinel EAD determine the relevant animal health status by keeping dust particles
suspended within the airflow until they reach our specialized capture media. This ensures
relevant samples from currently housed animals.
Plenum swabbing collection efficiency can also be influenced by the collection technique of the
user, the number of plenums sampled by each swab and the common practice of batching swabs
can lead to potentially inconsistent sample collection and less-accurate colony health
assessments. The Sentinel EAD method provides maximum EAD collection in the most
consistent and efficient manner possible, while reducing labor and increasing colony health
Why is Sentinel EAD better than batching samples?
Batching swabs may be more convenient than submitting individual samples, but it comes at a
cost...the reduction of reporting accuracy. Facilities may accept the results of their batched
samples and/or the convenience of batching over dirty-bedding sentinel methods; however the
colony heath assessment will not be as thorough as Sentinel EAD/PCR assessments. If animal
health is paramount, Sentinel EAD/PCR testing provides an unmatched level of colony heath
assessment within a rodent facility.
Can you put more than one collection media into your test tubes?
The main benefit of the Sentinel EAD solution is the increased health monitoring accuracy. The
accuracy is increased due to a variety of reasons, two of which being the ability to capture
sufficient exhaust air dust on the specialized collection media, and the ability to harvest the
highest amount of material from the collection media for testing. Putting two collection media into
one conical tube would require changes to the washing process that would yield far fewer copy
numbers during the replication process. This diminished sensitivity would significantly reduce the
reporting accuracy by forcing agents below the threshold of detection. Batching could significantly
reduce the sensitivity of the Sentinel EAD system, and would not allow Charles River to provide
the level of diagnostics expected and required by the research community.
How is Sentinel EAD designed to help reduce the potential of false positives?
Concerns over residual nucleic acid have primarily arisen during swabbing in combination with
PCR. The Sentinel EAD system may not suffer from that issue, as it does not require lifting of
material using a sticky swab for testing. The likelihood that residual material would be re-
aerosolized and captured on the Sentinel EAD media is very low. Sentinel EAD captures airborne
dust that travels within the airstream in the Allentown manifolds and plenums. Testing has proven
that the Allentown air management system, the Sentinel EAD holder and specialized collection media
comprise a system that collects relevant and current EAD sample material.
Residual nucleic acids present after rack washing will be very limited in number, and will usually
reside outside of the main airstream within the Allentown rack. If collected by the airstream, the
residual numbers will be far below the copy numbers of all other agents present on the rack.
Additionally, if it is not an excluded agent, there is no need for concern regarding the health status
of the rack.
If excluded agents are detected on a rack using any testing method, the rack should be taken out
of service and thoroughly washed and sanitized. Once back in use, racks may contain some
residual DNA after washing that will show up on future colony health monitoring testing; but as
already stated, if it is not an excluded agent there is no need for concern regarding the health
status of the rack.
False Positives can be concerning, however False Negatives pose much more of a threat to
colony health status, and that is exactly why Sentinel EAD was developed...to give the most
thorough and accurate colony health assessment possible.
Why is Sentinel EAD a better method than other IVC manufacturers' EAD sampling programs?
All IVCs are not the same! Allentown's unmatched expertise in airflow, rack design and
manufacturing is the main reason why our Sentinel EAD system is the most efficient way to
capture EAD. Allentown is the leader of airflow design, airflow management, and experts on how
IVCs react within the research setting. Our engineering pedigree comes from years of airflow and
HVAC design at the commercial and residential levels. Our experts know airflow, and over the
past 20 years they have adapted proven methodologies to model the very unique airflow needs of
the laboratory animal housing market. Our expertise allows us to design air-handling systems for
IVC racks, and also design IVC racks with the appropriate plenum and manifold proportions to
make certain we deliver the most constant and reliable airflow to our IVC units...for the safety of
the animals and your personnel. This over-engineering of our airflow design is exactly what
allows us to capture the correct particle sizes, keep them in the airstream throughout the entire
journey through our manifolds and plenums, and have them captured on an expertly designed
collection mechanism on a specialized media.
Why is it important to keep the EAD within the airstream?
If the dust particles drop out of the airstream they will lay in the plenums and manifolds of the IVC
rack. The dust not reaching the collection media will not allow a thorough analysis of the colony
health on that particular IVC rack. Other IVC manufacturers have airflow and rack designs that
can actually promote dust falling out of their airstream...that is why they are not attempting to
collect EAD at a central plenum location like the Allentown method. Their plenum and airflow
design cannot hold the EAD within the airstream nearly as consistently or efficiently as Sentinel EAD.
Why is collecting EAD at the centralized plenum level a better method than collecting at a HEPA or pre-filter?
When developing Sentinel EAD, our engineering and airflow experts experimented with a wide
range of collection locations and media. Using a small piece of media at a HEPA or prefilter
location works to some extent, but there are major drawbacks:
- The media in those locations acts as a filter (meaning air has to pass through it)
- Acting as a filter means the filter will load with debris
- Once the filter reaches a maximum load, it will no longer collect EAD
- Due to this limitation, the "snapshot" of the rack health status is considerably shorter than the "snapshot" provided by Sentinel EAD.
- The loading of the filter also impacts the efficiency of the IVC system, disrupting the air changes and pressure in the IVC rack due to the loading of the filter
The Sentinel EAD collection media is a patented material that does not act as a filter. The
material composition, along with how it is positioned within the Allentown IVC plenum, allows
EAD to be attracted and captured without loading or any impact on airflow efficiency. This method
allows a longer historic time period to be sampled ensuring researchers will be able to analyze
health status of their animals throughout the duration of the sampling time period. It is this feature
coupled with the Allentown IVC rack's ability to keep EAD within the airstream, which allows
Sentinel EAD to be the best EAD sampling method on the market today.