Device Sterility Guidances and Validation

Timothy A. Ulatowski, director of CDRH's Division of Dental, Infection Control, and General Hospital Devices, answers questions about device sterility guidances and validation.

The FDA 510(k) Sterility Review Guidance 2/12/90 (K90-1) explains what testing needs to be completed for submission when the device is shipped sterile. However, a few questions remain. How many complete test studies (cycles) are needed, 1, 2, or 3?

To determine the number of cycles needed for a particular sterilization process, FDA directs manufacturers to the relevant standard. If a relevant standard does not exist, then basic procedures for process validation should be used. The sponsor must demonstrate the reliability and reproducibility of the process. Multiple samples and tests must be used throughout the validation process to document that criteria have been met.

For EtO validation (ANSI/AAMI/ ISO 11135), it is important to demonstrate reproducibility over multiple validation cycles. However, for products validated using radiation sterilization (ANSI/AAMI/ISO 11137, Method 1), only a single sterility verification study must be performed, based on three lots of data.

What validation is needed when the user sterilizes a device—for example, if a device is shipped nonsterile but will be sterilized by the hospital with EtO before each use?

FDA directs manufacturers to the guidance document titled Guidance on the Labeling of Reusable Medical Devices for Reprocessing in Health Care Facilities: FDA Reviewer Guidance, April 1996, and to the AAMI Technical Information Report (AAMI TIR No. 12-1994) titled Designing, Testing, and Labeling Reusable Medical Devices for Reprocessing in Health Care Facilities: A Guide for Device Manufacturers.

These documents require the manufacturer of a reusable device to provide adequate (re)processing information in labeling. The users should not be burdened with the responsibility of validating sterilization processes for reusable devices—many do not have the resources for such testing. However, the user must have the equipment described by the reusable device manufacturer and must follow the instructions. If the user deviates from the labeling, then it is the user's responsibility to ensure that the sterilization process used is safe and effective.

If labeling does not contain critical information about sterilizing a reusable product (e.g., if it does not provide aeration time), then the user should contact the manufacturer for more information.

Another recently approved guideline may serve as a reference for the handling and biological decontamination of medical devices in health-care facilities and nonclinical settings. This guideline is ANSI/AAMI ST35-1996, Safe Handling and Biological Decontamination of Medical Devices in Health Care Facilities and in Nonclinical Settings, 2nd ed.