Hi all, for the past two weeks, i was attached to the histology lab. It was really a eye-opening experience i saw a lot of interesting things that i had never seen before, like the pathologist sectioning different organs and also observed post-mortem by the professor there. It was rather scary esp for the post mortem done on pre-mature babies.
Yup, but for this entry, i am going to share aboutfrozen section.
What is it? For frozen section, it is only done for emergency cases. It is done when the patient in the operating theatre and the doctor needs to know if that particular part of the tissue/organ is cancerous or if they have any benign tumors. The doctors would need to know if the margins pf tumors are clear. So what usually happens is they will take out a small section of the part of the tissue and sent to the lab for diagnosis. And as I mentioned they are still in the middle of the operation, they will need the results fast. Therefore, the whole process from the moment the pathologist starts to section to reading the results under the microscope.
When the tissue/section is cut out by the doctors in OT and ready for collection, the staff in the lab will go to the OT to collect the specimen. The section is sent fresh, which means no formalin is used to fix it etc. Tissues are collected in an ice box.
Specimen received must not be sent in formalin, but sent fresh. It will also not be performed for tissue from patients suspected of tuberculosis and other high risk infection like HIV, HBV and HCV etc.
All the patients name, accession number, specimen type, diagnoses are to be recorded down in a handbook for referring purposes. The pathologist will be the one sectioning and there will be a medical technologist to assist them in recording the morphology and dimensions of the specimen sent down. Specimens with history of infection will be handled in the BSC.
All types of tissues can be sent down as long as they are from the human body, usually the more common ones sent down are sections of breast tissue, uterus, gynaecology, cervix and etc.
Procedures Preparation -A small amount of O.C.T (optimum cutting temperature) compound is added onto a semi-cold specimen disc. (It is to hold the tissue on the disc and acts as an embedding medium) - The tissue will be placed on the O.C.T compound - The tissue will be covered with more O.C.T compound until the entire section is covered. - It is then quickly placed in liquid nitrogen to freeze the specimen rapidly - The section disc is inserted into cryocut and the heat extractor cylinder is used to flatten the surface for easier sectioning.
Sectioning - The frozen section is performed using the LeicaCryocut 1800. The interior of this machine is around -20 to -30 degrees Celsius - The tissue sections are cut at 5micrometers - The sectioned specimen were then picked up by using a warm glass slide, the specimen will be attached to the glass slide by itself when it touch the surface of the slide. - It is then to be stained with Rapid H & E. (used usually as when viewed under the microscope, this stain will give enough contrast and allow better diagnosis)
Staining - The section fixed in - 10% formal alcohol for 20s - Rinse in water - Haematoxylin for a min - Rinse in ammonia water - Wash - Eosin for 15s - Dehydrate in 2change of alcohol and 2 change of xylene. - Mount in DPX
Lastly, the pathologist will view the slides under the microscope and interpret the results. ( to see if there are tumors seen etc.)
