As with any specimen collection process, facility procedures must be adhered to in order to prevent errors and specimen rejection. Errors that are generated during the collection and grossing phase are termed pre-analytic errors. The list below addresses the most important procedural aspects that help to maintain accuracy and prevent pre-analytic errors:
- The specimen container(s) must be labeled with appropriate patient identification (ID) information and the site(s)/location(s) of skin sample(s) (such as left upper arm or mid upper back).
- The patient order form or requisition must also contain appropriate patient ID and the site(s)/location(s) of the skin sample(s).
- The patient ID and site(s)/location(s) must match on both the specimen container(s) and requisition. Specimen mix-ups typically occur when specimens being processed are similar (like skin biopsies or colon biopsies). Therefore, it is critical to have controls in place to prevent such mistakes. Even a mix-up within multiple specimens from one patient could be detrimental if a sample from the "face" was 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 liquid fixative to tissue ratio is 10 to 1, or fixative volume should be at least 10 times the volume of the specimen. When considering which formalin-filled container to use for a sample, a container that is at least three times the size of the specimen should allow the specimen to fix properly. Excisions should not be placed in small biopsy containers.
- Once the tissue is placed in a formalin-filled container, verify that it is completely covered with formalin. 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 solution, rather than formalin.
- Specimens for hematoxylin and eosin (H&E) frozen sections or Mohs do not require formalin fixation prior to freezing. Therefore, do NOT submit 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.