Why does cytology always have no diagnostic information? Talk about methods and details

Why does cytology always have no diagnostic information? Talk about methods and details

Fine needle aspiration, imprint smear, and cytological examination of coelomic exudate can provide important information and often help determine the success or failure of a case. Cytology is a popular diagnostic tool because it is less invasive than a surgical biopsy. In addition, cytological tests are less costly and faster than histopathological tests. Cytological examination can often provide a definitive diagnosis or narrow the differential diagnosis by selecting appropriate cases, good sampling procedures, and correct smear preparation.

However, cytology can also be a frustrating task for clinicians, pet owners and pathologists. Useful conclusions may not be obtained when case selection or sampling and preparation techniques are not ideal. The main problems with not getting a good cytological smear are missed sampling lesions, too few exfoliations or cells that can be sampled (which may be due to the technique or type of lesion), excessive hemodilution, excessive sample thickness, cell rupture during processing, and sample destruction during collection/preparation. Cytology itself and the structure of the tissue can’t detect this birth defect. Even when limited by the structure of the tissue itself, cytology is a useful screening tool and can be used as a complement to histology.

A precipitated staining solution (canine blood smear). Note the dotted aniline blue material at the top and between the cells. The precipitated staining solution may be mistaken for Mycoplasma haemophilus; And of course you can see these staining solutions between the red blood cells, and if you look up and down a few times you can see that it’s the same thing.

Case selection and successful sampling are the first steps in obtaining high quality diagnostic cytological specimens. Cytological examinations may be performed for body cavity effusions, fluid from mass lesions, swabs of effICULtor tracts and ears, fine-needle aspiration biopsies of masses and organs, airway irrigation, imprint smear on surfaces of masses and ulcers, bone marrow and cerebrospinal fluid (CSF). Any sample that can be painted on a  and stained can be examined under the microscope, but the clinician’s expectations should be adjusted according to the sample. For example, cytological examination of nasal rinse and nasal mucus usually reveals inflammatory cells and bacterial microorganisms, but rarely contains tumor cells or fungal microorganisms, even though tumor or fungal infections are the main underlying disease.

A mass less than 0.5 cm (5 mm) in diameter may be too small for the needle tip to be inserted into the lesion to cover the inclined surface of the needle, making aspiration difficult. Fine needle aspiration biopsy (FNAB) can still be attempted on these very small lesions, but only if the patient is prepared with or without a sample of diagnostic information.

The next pitfall is getting the samples right. It is important to disperse the samples into a single layer so that the cells can be isolated from the blood and properly evaluated under a microscope. Care must be taken, however, not to put too much pressure on the glass slides microscope and break the cells. But overcaution often leads the prudent physician to drain the syringe’s suction onto the slide without diffusing the sample. This can lead to “blood splatter smears”. In this case, the cells still congregate in the sticky areas of the blood, clumping together and condense into clumps, making it difficult to assess cell morphology. All samples used on the microscope glass slides should be properly dispersed to obtain the best diagnostic information.

To properly diffuse the cytological sample, apply the sample to one end of the microscope slide glass (preferably close to the frosted edge of the microscope slides lab). Then another slides microscope is placed on the sample. Use microscope slides laboratory s to weight disperse samples. Do not apply extra pressure – this may rupture the cell. Pull the two slide glass microscopes apart on the same plane until there is no contact. Do not separate the upper and lower microscope slides manufacturers too soon, as this can cause the cells to rupture.

Once the cytological glass slides microscope laboratory is ready, it is quickly dried and air fixed. Prolonged drying results in cell shrinkage, making the nucleus and cytoplasm indistinguishable from each other and making it difficult to assess the nuances of cell morphology. Most well-dispersed samples dry out quickly on their own, or can do so by gently swinging the air back and forth. Thicker smears, including samples of synovial fluid and mucus, should be manually dried using a fan or hair dryer in a cold air condition to avoid slow drying artifacts. slides for microscopes should be completely dry before being sealed into plastic medical microscope slides boxes, as this can create artificially damp conditions and the cells on the disposable medical microscope slides can rot and rupture during transport. Do not heat the stationary laboratory microscopic slides – it is not necessary and may damage the cells.

Repeated aspiration of the same lesion increases the chance of success. In fact, only one high quality glass microscope slide is needed to make a diagnosis, but it may take three or four slides to produce a slide of diagnostic quality. An additional complication for veterinarians in making cytological samples is the uncertainty that they have the necessary samples before they are sent for testing. This is very different from biopsy and formalin fixation, where the veterinarian sends a piece of disordered tissue, which is a fairly clear result. It is necessary to select 1-2 cytological slides for staining and rapid examination of cell properties in the hospital. If no nucleated cells are present or only a few are seen, consider doing more pumping. Specialist laboratories certainly have excellent microscopes of high quality, but no microscope can make cells grow from nothing. Samples submitted for examination always include stained and unstained, air-dried hospital slides for the most comprehensive assessment.

Impression smear is another method of making cytological samples. It can be made from ulcerative external lesions or biopsy tissue. As mentioned above, imprint smears of ulcerative lesions often provide information about the lesion’s surface, so prepare concurrent FNAB or tissue biopsy to obtain a definitive diagnosis. In addition, after the initial imprint smear with the ulcer, the top layer of the ulcer can be gently removed, the imprint smear made with clean, deeper, exposed tissue, and/or the scalpel can be used to scrape off the cellular material that may spread to the glass slide. However, these smears tend to be blood-heavy and the results are difficult to analyze.

The imprint smear of the biopsy should be derived from the surface of the newly cut tissue. Gently wipe the surface with a paper towel until there is no blood. When you’re done, press the tissue tightly onto the slide and lift it directly up. Can be repeated many times on a clean part of the same slide. The effect should be similar to a lip print on a wine glass. If the imprint smear looks bloody, continue drying until the imprint smear has a bloodless, membranous appearance. Drag or smear along the slide on the surface of the newly cut tissue will not produce a good smear.

Cytological swabs are samples taken from mucosa (vagina), ears, and secretions from fistulas. The sampling surface must be moist so that the sample is close to the tip of the cotton swab. Simply insert a sterile cotton swab into the area/lesion to be sampled and gently wipe the cotton tip along the wet surface. Remove the swab and gently roll the tip of the swab along the slide surface. Do not drag or smear the sample on the glass surface. If the sample on the slide is thick and wet, you can use a fan or hair dryer set to cool air to assist air drying. Fluid cytology can be used for body cavity effusion, airway flushing fluid, synovial fluid, mass secretion, and urine. Fluid cytology, especially coelomic effusion, is an essential part of a complete examination and usually yields a definitive diagnosis. For all liquids sent for external inspection, the liquids should be placed in the EDTA tube. In addition to preventing blood clots from forming in samples, EDTA is also an excellent cell preservative. If liquid culture is expected, it is recommended that a sample of the liquid from a red-top tube (RTT) or other sterile container without additives be tested as well. EDTA has antibacterial effect and can affect the results of culture. Finally, if the liquid sample cannot be delivered to the laboratory immediately, some direct (non-concentrated) smears can be made, dried and submitted with the EDTA sample tube. Cells in the fluid degrade over time, even in EDTA, and the slide sample you send out of the EDTA sample tube helps the pathologist understand the baseline state of the cells at the beginning of sampling. If a floccus or mucous gel is present in the airway rinse fluid, this material may be useful for compression or imprint smear.

Cerebrospinal fluid is a special fluid that is delivered and processed in a unique way. Unless the fluid is heavily bloodstained and anticoagulants are required, CSF is usually collected into the RTT. The sample size, cell count, and protein content are usually low, and EDTA can dilute the sample, so the cell count may change. The low protein environment of CSF in vitro leads to rapid cell degradation. There are many ways to preserve cells during laboratory submission, including the addition of autologous serums, hydroxyethyl starches and even formalin. However, studies have shown that even in samples with very low protein content, pathologists can reliably identify and classify cells 24 hours after the sample is taken. However, it is still recommended to treat the cerebrospinal fluid as soon as possible after sampling. Sample handling is best handled by a professional laboratory.

The key factors to obtain the best pathological analysis are good sample collection, good sample distribution and sufficient clinical information. Following the above recommendations and continuous clinical practice can greatly improve the diagnostic effect of cytological examination.

Jiangsu Huida is a manufacturing enterprise specialized in providing microscope slide. The company sets research and development, production, sales and after-sales service as one, to provide customers with microscope slide. After years of development, the company has been adhering to the “customer first, excellence” business philosophy, adhere to the “customer first” principle to provide our customers with quality services