A fresh, un-fixed surgical tissue biopsy arrives in the histopathology laboratory and is immediately placed into a container of 10% Neutral Buffered Formalin (NBF) by the laboratory staff. Ten minutes later, the operating room surgeon calls the lab and requests an immediate frozen section on that tissue to determine intraoperative margins. What is the best action the MLT could take?

Prepare for the CAMLPR Specimen Collection Competency Test. Practice with diverse question sets including multiple-choice and flashcards. Each question includes hints and explanations to help you become proficient before the exam.

The main concept is that intraoperative frozen sections require fresh, unfixed tissue. Once tissue has been placed in formalin, fixation begins immediately, causing chemical cross-linking of proteins and changes in tissue water content. These changes make the specimen unsuitable for reliable rapid freezing and cryosectioning, so attempting a frozen section on fixed tissue would produce artifacts and an unreliable diagnosis. Because of this, you inform the surgeon that a frozen section cannot be obtained from tissue that has been exposed to formalin. A fresh specimen would be needed, which may require a new biopsy or other arrangement, rather than trying to salvage the current fixed tissue. This protects the accuracy of the margin assessment and the safety and workflow of the lab.