What Is Liquid Based Cytology?

Liquid-based cytology is a part of exfoliative cytology. It is to put exfoliated cytological specimens that are difficult to handle in a traditional way into an intermediary fluid to remove blood and mucus, which interfere with the diagnosis, and improve the diagnosis rate. purpose.

Liquid-based cytology

Right!

Liquid-based cytology is a part of exfoliative cytology. It is to put exfoliated cytological specimens that are difficult to handle in a traditional way into an intermediary fluid to remove blood and mucus, which interfere with the diagnosis, and improve the diagnosis rate. purpose.

The intermediary fluid is called cell preservation fluid, which has the functions of maintaining cell morphology, softening mucus, and processing red blood cells.

Exfoliative cytology is a method that uses normal exfoliated cells from human tissues for diagnosis, such as cervical scraping.

Chinese name

Liquid-based cytology

Foreign name

TCT

One: What is liquid-based cytology? ^[1]

2: Application scope of liquid-based cytology

Cervical scraping, pleural and ascites fluid, puncture fluid, sputum specimens and other exfoliated cytological specimens, typically used for cervical scraping.

Three: liquid-based cytology specimen processing method

Centrifugation method and membrane type negative pressure suction method (referred to as TCT), centrifugation method is divided into natural sedimentation type (referred to as LCT) and centrifugal shaker type

Four: the principle of centrifugation

The centrifugation method is to fully shake the sample and put it into a centrifuge tube for centrifugation. The diagnostic components such as epithelial cells are aggregated and adhered to the bottom of the centrifuge tube to form a cell cluster, and then the liquid on the cell cluster is discarded (the liquid contains red blood cells, mucus and other components). To achieve the purpose of removing interference components.

Five: Natural sedimentation film production process

1: Place a drop of cell adhesion agent on the center of a glass slide (note that the frosted surface is up and leave the frosted surface), cover the second slide with the front side down and flatly cover the first slide for 5 minutes Pull horizontally and dry.

2: Number the specimen on the centrifuge tube.

3: Shake the specimen for 1 minute, and then pour the specimen solution into a 15 ml centrifuge tube with the specimen number.

4: Put the centrifuge tube into the centrifuge at 1000 rpm for 2 minutes.

5: Discard the supernatant and add 1 ml of buffer and shake the cell pellet for 10 seconds.

6: Mark the dried slide with the specimen number, place it in the production board, and lock the production chamber.

7: Thoroughly mix the specimens and pour them into the production chamber in order. After 8-12 minutes, discard the specimen liquid from the production chamber, rinse it with alcohol, and then stain (can be stained in the tank).

8: Add five drops of hematoxylin staining solution, and rinse three times with buffer or tap water 3ml after one minute of staining.

9: After adding 0.5ml of alcohol to decolorize, add five drops of EA / OG and stain for one minute.

10: Rinse well with alcohol, seal the slide after xylene is transparent.

Six: Advantages of Natural Subsidence Production

1: The production background is clear, and the cells are distributed uniformly without overlap.

2: Because the density of positive epithelial cells is greater than that of normal epithelial cells, they are preferentially captured by cell adhesion agents after sedimentation, and the positive rate is high.

Seven: Disadvantages of traditional cervical scraping

1: Use scraping tools, cotton swabs, etc.

2: Impurities such as blood and mucus cover the cells and cannot be observed with a microscope.

3: Cells overlap.

The above three factors result in a low diagnosis rate.

Eight: Liquid-based cytology advantages

1: Use a special cervical cell brush to obtain the material. The material is comprehensive.

2: Removes impurities such as blood and mucus.

3: Cells do not overlap.

Therefore, the diagnosis rate is high.

Nine: Principle of membrane negative pressure suction method

After the sample is thoroughly mixed, insert a tube-shaped object with a film at the lower end into the sample liquid vial. A negative pressure pump is connected to the upper end of the tube-shaped object. There are many holes on the film that are smaller than the epithelial cells, larger than the small particles of mucus, and the white blood cells. Negative pressure suction allows the epithelial cells to stay on the membrane and allows mucus and white blood cells to pass through the membrane to achieve the purpose of removing impurities. But blood cells also remain on the membrane, making the processing of impurities incomplete. Due to cervicitis, patients with cervical erosion have a clinically obvious manifestation of blood contact (ie, bleeding at the slightest touch), which causes a large amount of blood in the material to be collected, which causes trouble for specimen processing. Domestic membrane-type machines require doctors to take materials for use The small force makes the material acquisition incomplete, which reduces the positive rate.

Ten: Principle of Centrifugal Shake Method

After thoroughly mixing the specimens, take a portion of the specimens into a special centrifuge cup. A glass slide is attached to one side of the centrifuge cup. After centrifugation, the cells are left on the glass slide, fixed with alcohol, and stained. This method can only process part of the specimens, and the background of the film production is unclear. The amount of cells on the film varies with the amount of material taken.

Production and sales of liquid-based cytology consumables