As with any specimen collection process, facility procedures must be followed to prevent errors and rejection. Errors generated during the collection and grossing phase are termed pre-examination (formerly pre-analytic) errors. The list below addresses the most critical procedural aspects that help to maintain accuracy and prevent pre-examination errors:
- The specimen container must be labeled with appropriate patient identification (ID) information and the site/location of the skin sample (such as left upper arm or mid-upper back).
- The patient order form or requisition must also contain the appropriate patient ID and the site/location of the skin sample.
- The patient ID and site/location must match on both the specimen container and requisition. Specimen mix-ups typically occur when similar specimens (like skin or colon biopsies) are processed. Therefore, it is critical to have controls to prevent such mistakes. Even a mix-up within multiple specimens from one patient could be detrimental if a sample from the "face" were placed in a container labeled "chest."
- An appropriately sized, formalin-filled container must be used if the tissue requires fixation for paraffin processing. For optimal tissue fixation, the volume of formalin must be at least 15 to 20 times that of the specimen. Inadequate formalin volume will result in insufficient fixation since formalin molecules deplete as they bind to the tissue specimen. When considering which formalin-filled container to use for a sample, a container at least three times the size of the specimen should allow the specimen to be fixed correctly. Excisions should not be placed in small biopsy containers.
- Once the tissue is placed in a formalin-filled container, verify it is completely covered. If the specimen is not free-floating in the liquid, a larger container with more formalin should be used for the sample. This is particularly critical for large excisions.
- Specimens that require immunofluorescence (IF) should be preserved in Michel's media rather than formalin. Michel's media is a preservative that allows frozen sections to be performed as required for successful IF staining. Michel's does not fix the tissue sample.
- Specimens for hematoxylin and eosin (H&E) frozen sections or Mohs do not require formalin fixation before freezing. Therefore, do not submit specimens in a formalin-filled container.
The laboratory accepting the specimens for grossing and processing must receive appropriately labeled specimens, in appropriate fixative, with matching paperwork. Any errors should be resolved before proceeding to the grossing stage.
