3rd week of SIP

Name: Hardina Bte Hamzah

Topic: Histology
There are many processes that take place in Histopathology Laboratory.
Firstly, specimens will be sent by the portal assistant. There are steps to follow when receiving the specimens. We need to check the information on the requisition form against specimen bags or bottles to ensure it tallies. The specimens will then be given specific numbers as identification. We must ensure that the specimen bottles or bags are labeled properly to ensure accuracy. Formalin is present in each packaging to preserve the specimens.

The specimen will be inspected by the medical technologist or assistant pathologist after receiving. The gross description of the specimen is recorded. The specific parts of the specimen will be taken and placed in cassettes to be processed. Specimens that have been placed in cassettes will be loaded into a tissue processor. All the reagents needed are present in the tissue processor. For example, reagents like formalin, alcohol, xylene and wax. The specimens will undergo dehydration to remove water and immerse in xylene to remove excess alcohol. Then they will be exposed to hot liquid paraffin turning soft, moist tissues into a sample miscible with paraffin. This process will only be done at the end of the day as it takes 14 hours to finish.
When the tissue processing is done, drain out all the excess wax present in the chamber before taking out the specimens. Embedding is done after tissue processing. Wax is half-filled into embedding mould and the tissue is placed inside. The tissue is pressed down so that all the parts of the tissue will be exposed when it is cut into thin sections. Then, the base of the cassette is placed on top of it and more wax is added. The mould will be put on ice to cool is faster. After it cools, the paraffin block is removed from the mould. After embedding is done, the baskets will be loaded into the tissue processor and flushing will occur. This process will remove the excess wax and clean the baskets.

The paraffin block is cut into thin sections (3µm) by using microtome. We must be very careful when using microtome as the blade is sharp and can injure our fingers. After sectioning, the section is placed into a water bath with the temperature between 43-50°C to allow the section to expand. Then, fishing is done by orienting section properly onto slide. We must maintain the water bath at the correct temperature and free of debris to prevent contamination. The work area has to be cleaned daily to ensure cleanliness.

The slides with the tissue on them will be placed in the oven of temperature between 85-90°C to melt the wax and fix the tissues on the slides. Then, the slides are loaded into the autostainer to undergo H&E staining. Firstly, it will hydrate the tissues (1. Xylene: to remove wax, 2. Alcohol: to clear xylene) and stain with haematoxylin. Then, wash the slides to remove excess haematoxylin. The tissues are then stained with eosin and later undergo dehydration (1. Alcohol: to remove water, 2. Xylene: to clear alcohol). Depex are then placed on the tissues followed by coverslips. This is done by a machine. This process is mainly automated.
These slides are then labeled and re-checked against paraffin blocks to ensure no mistake is done before sending them to pathologist.

Topic: Cytology
Conventional Pap Smear
Pap smear is the smearing of cells from the cervix and staining it with Pap stain. The pathologist will then observe the slides to see if there are any cancerous cells or infection.
Firstly, I will explain on how to obtain the sample and make a smear.
1. Insert a broom-like device into the vagina.
2. Ensure that it comes into contact with the ectocervix.
3. Gently push the device and rotate clockwise for 5 times to ensure that enough cells are collected.
4. The doctor will then smear the cells onto a glass slide thoroughly and spray-fixed the smear before sending to the lab.

However, several problems have been discovered when using the conventional Pap smear.
After the cervical sample has been collected using the broom-like device, the cells will be smeared onto the slide. However, over 80% of collected sample is discarded and higher chances that the cancer cells will not be smeared onto the slide. After staining the slide, it will then be observed under the microscope. Due to the smearing technique, the cells tend to clump together and will have difficulties to identify cells. In addition, as 80% of collected sample is discarded, there will be missing cells which restrict from producing an accurate diagnosis. It will not reflect the patient’s actual condition.
Therefore, a new method is introduced.

Liquid- based Cytology (LBC)
After cervical sample is collected using the broom-like device, the device will be rinsed into a vial containing preservatives. This ensures that 100% of collected sample is present in the vial and no cells are left on the device. This sample will then be processed using a processor. This process is automated. The processor will stir the solution in the vial to disperse the cells. Cell will be collected onto a filter by suction. Cells will then be transferred onto a slide by making the filter come into contact with the slide. This will produce a thin layer of cells and minimize the clumping of cells. With this, it will allow the pathologist to detect any abnormalities.