Breast specimens should be immersed for 6-72 hours.<ref>{{cite web|url=https://webapps.cap.org/apps/docs/committees/immunohistochemistry/her2_faqs.pdf|title=Recommendations for HER2 Testing in Breast Cancer: ASCO – CAP Clinical Practice Guideline Update|date=2013-10-17|website=College of American Pathologists}}</ref>