Radiation Quarterly Dose Audits (QDAs)

What is Radiation Sterilization Validation?

A Radiation Sterilization Validation is defined as the dose of radiation necessary to produce a 90% reduction in a number of indicator microbial cells, which determines the appropriate radiation sterilization dose for a product that requires a sterile label claim. It depends on many factors including temperature, moisture, organism species, chemical environment, or physical surface on which indicator microorganism is attached. Bacillus Pumilus spores are USP choice as a biological indicator for radiation sterilization. This includes bioburden testing, the bioburden recovery efficiency test, a radiation dose verification, a test of sterility, and bacteriostasis or fungistatic testing.

What are Quarterly Dose Audits?

Quarterly Dose Audits are used for monitoring the frequency of Audits (Quarterly, with a possible reduction in frequency), verification Dose, and arguments Dose if product Audit fails. A Dose Audit is an effective program to control microorganism levels in the manufacturing environment which is essential to minimize the bioburden on the medical device being manufactured.

"Sterilization of health care products – requirements for validation and routine control – radiation sterilization", ISO 11137 gives out certain criteria that should be met prior to the production of medical products, outlines the general procedures to audit the sterilization dose to ensure the validity of the dose despite the change in the manufacturing process.

Verification methods

Bioburden test determines the number of viable microorganisms on or in the product. This test is performed prior to any sterilization but after all other manufacturing steps, including packaging. Critical to this test is the performance of a recovery efficiency test to determine the effectiveness of the bioburden extraction method at removing microorganisms from the product. Other options for performing bioburden are available and may be more appropriate for certain product types.

The sterility test is the irradiated products that undergo a test of sterility. Critical to this test is the performance of a bacteriostasis/fungistatic test to demonstrate the lack of inhibition in the sterility test system, which is required to validate the test of sterility.

The bioburden results are taken to a table from the standard to determine the proper verification dose. The verification dose is then applied to the required number of products.

If the number of nonsterile samples in the test of sterility meets the acceptance criteria, the radiation sterilization dose is validated. Additional testing should be performed on a quarterly dose audit to demonstrate that the sterilization dose continues to be appropriate for the product. The quarterly dose audits only involve samples from a single batch, and include the use of the verification dose determined in the validation rather than setting a new one.

STEMart offers Radiation Quarterly Dose Audits Services following the radiation sterilization standard ANSI/AAMI/ISO 11137 and technical specification ANSI/AAMI/ISO 13004.

If you have additional questions about Radiation Quarterly Dose Audits Services or would like to find out more about our medical device services, please feel free to contact us.