Molecular Diagnostics Services, Inc.
A Contract Research Organization

Sterility Test Validation Note

It is important to determine if the test article that will be tested for sterility contains elements that will interfere with the growth of microorganisms within the growth media used for the assay. This validation testing is commonly referred to as a Bacteriostasis/Fungistasis (B/F) test. The validation test is typically required only once for a given sample type, provided that no additional changes to the source, product, formulation or manufacturing process occurred. However, validation testing could be performed on a periodic basis to confirm that no significant changes have occurred to the product or process that may affect the sterility assay results. MDS offers Sterility testing and Sterility test validation (B/F test). These testes can be performed individually or concurrently. At the client's discretion, once the sterility test is completed, the post-sterility-test samples can be used for the validation testing to avoid the use of additional samples

Sample Requirements by Test Article Type

Batch Size

Minimum Number to be Tested in Each media

100 or less

10% or 4 containers, whichever is greater

101 – 500

 10 containers


2% or 20 containers, whichever is less

Bulk– Up to 4 containers

Each container

5 – 50

20% or 4 containers, whichever is greater


Volume / Container

Minimum Quantity to Test in Each Media

Less than 1 mL

The entire contents of each container

1 – 40 mL

Half the contents of each container but not less than 1 mL

41 – 100 mL

20 mL

>100 mL

10% of the contents of the container,
but not less than 20 mL

For information regarding available sterility assays or to discuss the sterility test method most appropriate for your sample type, please contact us
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