It is often desirable or necessary to test fluid samples, such as liquid specimens, for contamination by live microorganisms. The presence of microbial contamination in clinical specimens is conventionally determined by culturing the specimens in the presence of nutrients and detecting microbial activity through changes in the specimen or the atmosphere over the specimen after a period of time.
It is often desirable to be able to test a specimen having a relatively large volume. Furthermore, it may be advantageous to increase the concentration of microorganisms in the specimen undergoing analysis so that changes in the specimen or adjacent atmosphere are intensified and thereby more easily and accurately detectable.