Individually ventilated cages are widely used all over the world as one of the most powerful tool for the protection of laboratory animals from microbial contamination. An evaluation on the efficiency of the system was carried out by a group of scientist at "Istituto Superiore di Sanità" (National Institute of Health) in Rome.
The IVC Top-Flow system (Tecniplast Gazzada S. a r. l.) was tested using two different air (volumetric) sampling methods to compare the detection capacity of the two techniques and the correlation.

The air sampling methods used were:
1) Surface Air System (SAS)
2) All Glass Impinger (AGI-30)

The test was performed running the equipment either in positive or negative pressure and using as a standardized contaminant the non pathogenic bacteria Pseudomonas fluorescens.
The intra-cage sampling confirmed the capability of the IVC Tecniplast system to protect the inside of the cage coming from the external environment.

The authors have developed a sensitive and efficient validation method capable to stress an IVC Top-Flow system through the use of an highly concentrated microbial burden and double checking the results with two sampling methods.

Reference is the following:

Borrello P.,D'Amore E. Panzini G. Valeri M. & Lorenzini RN. Individually ventilated cages .
Microbiological containment testing. Scand.Journal of Lab.An.Science 2000. N°3 Vol.27, 142-152.