Fixation on Histology

Everyone knows someone who looks at expiration dates as a friendly suggestion. It may be okay to eat bread a few days past its expiration date, but the materials we use in our labs have expiration dates too, and this is something that CAP checks on. Take for example, reagents. ANP .21382 on the CAP checklist requires that “All reagents are used within their indicated expiration dates.” If there is not a manufacturer provided expiration date, it is up to your laboratory to assign one.

Obviously, this isn’t something that is just assigned arbitrarily. In order to be CAP compliant, your lab must have a written policy for evaluating reagents that are lacking an expiration date. CAP suggests that you take into account “stability, frequency of use, storage conditions, and risk of contamination” but you should also develop a procedure for validating and re-testing these reagents, against proper controls, to show that they are functioning as they should be. This testing process should be documented, with a label on the reagent, forms in a binder, and/or tracking in a computer system; whatever your lab is currently using to maintain these types of records. Check out some sample re-testing forms in the NSH resource library on The Block.

Having a testing process for your reagents is important, even if a reagent is not subject to outdating and it doesn’t need an expiration date. CAP requires that reagents not needing an expiration date be confirmed as functional by “technical assessment”, which they specify as use in actual case material with suitable control sections as part of a pathologist’s diagnostic evaluation of a case. This assessment must also be documented, and a system put in place for regular, yearly, reassessment. A label on the reagent should be applied, indicating the date it should be re-verified through technical assessment.

There is also another exception to the expiration date ruling; laboratories not subject to US regulations. As histologist, Dave Davis, mentions in his podcast on histology in Ghana, not every country has easy access to the supplies they need for everyday lab work. CAP recognizes this in their international exceptions to reagent expiration. Non-US laboratories may use expired reagents when the reagents are unique or difficult to obtain, or if delivery of reagents is delayed because of causes beyond the laboratories control. (Even in these cases, laboratories are still expected to follow their written procedures for proving that the reagents are functional, however.)

Note: These standards are for labs seeking CAP accreditation, however you will find that CLIA and FDA standards are very similar!

References:

https://www.nsh.org/viewdocument/re-reagents-without-expiration-dat?CommunityKey=007ca8ea-3c4f-4359-b441-44ef10bc9dad&tab=librarydocuments

https://www.nsh.org/communities/community-home/digestviewer/viewthread?GroupId=13&MessageKey=a5071e5a-7abc-4942-828a-55021fbe170e&CommunityKey=007ca8ea-3c4f-4359-b441-44ef10bc9dad&tab=digestviewer&ReturnUrl=%2ftheblock%2fbrowse%2fallrecentposts